The 2018 election cycle has officially begun, with the first primaries being held in Texas on Tuesday.
In every campaign cycle, analysts look at the fundamentals — the political laws of gravity that, in the past, have influenced elections. In 2016, Donald Trump seemed to defy a lot of these laws, and Republicans are hoping they can do the same this year to prevent the hit that the party in power usually takes in a president's first midterm elections.
Here are five laws of political gravity to watch as the 2018 campaign plays out:
1. When a president's approval rating is below 50 percent, his party doesn't fare well at all
Historically, parties that hold the White House lose seats in midterms — even more when they also have complete control of Congress, and even more when the president's approval rating is under 50 percent.
The Republican Party has a bad news trifecta here.
Since the Great Depression, when a president's approval rating has been below 50 percent in his first midterm, his party has lost an average of 41 House and five Senate seats.
Midterms are a referendum on the president and his party. Trump is still popular with his base, but because he is so historically unpopular with so many other voters, his ability to help his fellow Republicans is diminished. His "strongly disapprove" numbers have been consistently higher than his "strongly approve" numbers.
The latest tracking poll from Gallup showed that 39 percent of Americans approve of the job Trump is doing, while 55 percent disapprove. And his approval rating in the RealClearPolitics average is a similar 40 percent approve, 56 percent disapprove.
2. The party with the intensity and enthusiasm on its side wins
Democrats have it — and it's fueled by animus toward Trump, just like Republicans in 2010 and 2014 were motivated by antipathy to President Barack Obama. (Democrats lost a total of 76 House seats and 15 Senate seats in those two Obama-era midterms.)
In the handful of special elections since 2016, and in the Virginia and New Jersey 2017 elections, Democratic turnout has been up. There are hundreds of new Democratic candidates running in races where Democrats have failed to field a candidate in the past, and polls consistently show that Democrats are more interested and enthusiastic about the 2018 campaign than Republicans.
As The Washington Post noted Saturday, about 1,200 candidates had registered to run as Democrats for the House by the end of 2017 — a clear record for a single party and the first time since before the wave election of 2010 that Democrats outnumbered Republicans at the same point in an election cycle.
3. When people are in a bad mood, the party in power suffers
Voters' attitudes about the state of the country — Are we in a recession? Are we at war? — is always one of the most important factors.
Americans remain pessimistic about the direction of the country. On average, just 35 percent think the country is headed in the right direction, while 56 percent think it is on the wrong track.
And this year, the measurement isn't working the way it usually does in at least one big respect. The direction of the country and a president's approval rating is typically tied to voters' views about the economy. But right now, the economy is doing pretty well — with Americans' attitudes about the economy reaching a 17-year high in a recent NBC News/Wall Street Journal poll — and increasing numbers of people are saying they like the GOP tax cuts.
So why isn't Trump more popular? In fact, he is suffering poor approval ratings with the very upper-middle-class, suburban voters who are probably benefiting the most from his tax cuts.
Amy Walter of The Cook Political Report said that it's as if voters are saying to the president, "Yeah, we feel good about the economy, but we don't really feel good about you."
There is a wild card on the economy — Trump's threatened tariffs and a possible trade war. On Monday, the president said that he didn't think there would be a trade war if he goes ahead with steep tariffs on imported steel and aluminum, but a few days earlier, he tweeted that "trade wars are good, and easy to win."
Republicans worry Trump's tariffs could undermine the stock market and economic growth — two factors they have been counting on to help them in November.
4. The party that has the structural advantages can sometimes mitigate damage
This is the bright spot for Republicans.
Even though many Democratic candidates have raised impressive amounts of money to stock their war chests, Republicans have a lot more outside money than Democrats do. The Koch brothers' network of conservative donors alone have pledged to spend a whopping $400 million electing Republicans this year, 60 percent more than they spent in the 2016 presidential election.
Many GOP congressional districts are also drawn to protect incumbents, and because Republicans control more state legislatures, they have overwhelmingly drawn those districts to advantage their party.
Republicans are hoping the mighty fortress of redistricting will help them defend against a big blue wave — if one materializes. They are trying to fight back against a state court ruling in Pennsylvania that redrew the state's congressional district and is likely to eat into the GOP's 13-5 statewide advantage in House seats. But challenges to maps drawn by Republicans in Wisconsin, Texas, Michigan and North Carolina are unlikely to impact the 2018 election.
5. The party that turns out their base usually wins
Who actually comes out to vote is an important factor in any election — and it's hard to predict. But it's especially true in midterms, when activists traditionally dominate. Consider: There is about a 30 percent drop-off in turnout from presidential to midterm years.
In 2016, Donald Trump surprised a lot of political handicappers when he got more rural, white, working-class voters to the polls than most turnout models predicted. And things are often favorable for the GOP in a midterm.
"The people who turn out the most tend to be older people, tend to be whiter people, tend to be people who are married, and tend to be people who are well educated," says demographer William Frey of the Brookings Institution. "Most of them tend to favor the Republicans."
But there's one flaw in that profile for Republicans — highly educated voters generally do not like Trump. In fact, more than half of white college graduates have strongly disapproved of him. And, since 2016, they have been turning out for Democrats.
This will make it harder for Trump to help Republican candidates in the kind of suburban districts won by Democrat Hilary Clinton in 2016. The suburbs are precisely where Democrats are hoping to build their comeback. Clinton won 23 districts where a Republican was elected to the House in 2016. Democrats need to pick up a net of 24 seats to take back the House.
What's more, Trump won independents in 2016, but they've flipped.
To make up for it, Trump needs to turn out big numbers of his white, non-college-educated supporters to the polls this year — just like he did when he defied the odds two years ago.
"Coalitions that are built in presidential elections don't always translate into midterm elections," Walter points out. "Just ask Democrats who were counting on the Obama coalition of 2008 to come out in 2010. They didn't."
RACHEL MARTIN, HOST:
We're in Dallas, Texas, today to mark the first primary in the country ahead of the fall midterm elections. Democrats are feeling confident. And if you want to know how seriously Republicans are taking that threat, Governor Greg Abbott said it pretty plainly recently. In an email to supporters a few days ago, he said, the early voting numbers for Democrats should, quote, "shock every conservative to their core." And it's true. Democrats are fired up.
UNIDENTIFIED PERSON: Grab some food, and let's go knock on some doors.
MARTIN: That was a campaign organizer at the headquarters for Laura Moser. She is running in the Democratic primary for the Texas 7th. The district re-elected Republican John Culberson in 2016, but it also went for Clinton over Trump, so Democrats hope they can flip it. Roxanne Cox (ph) is a campaign volunteer, and she says President Trump's election was a lesson to all the supporters gathered there.
ROXANNE COX: I didn't see it coming that - you know, that Trump was going to get supported. And so I feel like we were a little complacent in what we thought was going to happen. And I think now we've become incredibly active.
MARTIN: Across town, some Republicans were thinking the same thing. Josh Redelman (ph) was making calls for Kevin Roberts, who's running for Congress in the 2nd District.
JOSH REDELMAN: Don't get complacent. Don't think this is a lock. Yes, this is a strong Republican state, but we're not crimson red anymore. So it's just one of those things. Like, be vigilant.
MARTIN: So if there's any chance for the Republicans to generate that kind of enthusiasm, it might be on the back of President Trump. NPR's national political correspondent Mara Liasson reports.
MARA LIASSON, BYLINE: Historically, the party with the White House loses, on average, dozens of House seats in a midterm election. Donald Trump knows this.
(SOUNDBITE OF ARCHIVED RECORDING)
PRESIDENT DONALD TRUMP: You win the presidency, and you take it easy. And then they come and surprise you in the midterms. They call them the midterms.
LIASSON: One of them who studies the midterms is Amy Walter of The Cook Political Report. She starts each election cycle with a list of things she thinks could determine the outcome.
AMY WALTER: The president's overall approval rating, whether he's above or below 50 percent, and then the intensity factor - how energized is one party over the other? - and then the just overall mood of the country - are we in a recession? Are we in war?
LIASSON: This year, some of those factors lean to the Democrats. Others advantage the GOP. But some of them aren't working the way they have in the past. For instance, the president's approval rating has usually been tied to voters' views about the economy. Right now the economy's doing pretty well, and more people say they like the GOP tax cuts. So why isn't Donald Trump more popular? Amy Walter has a theory.
WALTER: Think about suburban voters for a second who have been very sour on this president. These are the kinds of people who do have 401(k) accounts, who should expect to see, if they are in a certain middle-class income, a little bit of money back from the tax cuts. You're not seeing that translate to the president. Yeah, we feel good about the economy, but we don't really feel good about you.
LIASSON: The other big factor is turnout - who will actually come out to vote? That's hard to predict. In 2016, Donald Trump got more white, working-class voters to the polls than analysts thought he would. Will that happen again this year? All we know, says demographer William Frey, is who has turned out in past midterm elections.
WILLIAM FREY: The people who turn out the most tend to be older people, tend to be whiter people, tend to be people who are married and tend to be people who are well-educated. Most of them tend to favor the Republicans.
LIASSON: But there's one problem for Republicans in that otherwise favorable profile - people who are well-educated. Remember in the campaign when Trump said, I love the poorly educated? Well, they loved him back. College graduates generally do not. This year, Trump needs more of his white, non-college-educated supporters to turn out, just like they did when he defied the odds in 2016. Amy Walter thinks that will be hard.
WALTER: Coalitions that are built in presidential elections don't necessarily translate into midterm elections. Just ask Democrats who were counting on the Obama coalition of 2008 to come out in 2010. They didn't.
LIASSON: But Trump is trying in every way he can to keep his base voters energized.
(SOUNDBITE OF ARCHIVED RECORDING)
TRUMP: Don't be complacent, OK? Don't be complacent because if they get in, they will repeal your tax cuts. They will put judges in that you wouldn't believe. They'll take away your Second Amendment, which we will never allow to happen. They'll take away your Second Amendment.
LIASSON: Speaking of the Second Amendment, the new debate about gun control in the wake of the Parkland, Fla., school shooting is a wild card that could help Democrats this year. Another wild card is the president's threatened trade war. He says trade wars are good and easy to win. But Republicans worry Trump's tariffs could undermine the stock market and economic growth, two factors they're counting on to help them. And here's another thing to consider. More than two-thirds of Republicans in the House of Representatives have never run in a midterm election where their party had the White House. They've got lots of advantages, more money than the Democrats, favorably drawn congressional districts, but they no longer have the luxury of being the opposition party. Amy Walter...
WALTER: And now they're really the incumbents because they control everything - the Senate, the House and the White House, of course. So while their congressional districts may have been drawn to protect that Republican incumbent, they've never been tested by the kinds of headwinds that they're going to be tested by in 2018.
LIASSON: So which is more powerful, a good economy, more campaign money and the mighty fortress of redistricting, or increased enthusiasm, higher turnout and a huge crop of new Democratic candidates? We'll find out in about eight months. Mara Liasson, NPR News, Washington.
(SOUNDBITE OF SOLAR BEARS' "WILD FLOWERS") Transcript provided by NPR, Copyright NPR.