The Blue Wave is real. That much emerged from Tuesday’s primary election race in Ohio’s 12th congressional district, where Democrat Danny O’Connor appears to have lost narrowly to Republican Troy Balderson in a historically conservative district.

While the GOP still has a chance to hold onto the House, and looks likely to keep the Senate, there are five factors combining to create a “Blue Wave,” and Republicans from President Donald Trump on down will have to focus and fight hard to stop it.

1. The agony of 2016. Nothing motivates an opposition party quite like the sting of defeat from the last election. That was true of Republicans after 2008, and it is especially true of Democrats after 2016, when they expected to win easily. The shock of the loss has sent some Democrats into conspiracy-theory craziness, but it has also motivated the party to organize more effectively to win whatever it can. Republicans cannot do much to stop Democrat enthusiasm — but they can do more to motivate their own voters.

2. Health care. Obamacare continues to be a disaster. But while Republicans have repealed or weakened important parts of it, they have not replaced it with something better, and the cost of health care continues to plague middle-class families. Democrats have a terrible alternative — socialized medicine, i.e. “Medicare for All” — but at least they have a plan. The best argument against GOP control of both houses of Congress is that they could not find a solution even with near-complete control of the government.

3. The border wall. Trump and his supporters can rattle off a long list of “promises kept”: tax cuts; economic growth; jobs; one Supreme Court justice confirmed and another on the way; withdrawing from the Paris Climate Accords; ending the Iran nuclear deal; and more. The one glaring exception is the border wall, which Trump claims has already begun but which has yet to find the necessary funds, either from Congress or from Mexico. The failure to keep this core promise could keep Trump voters home.

4. The tone. Trump likes to fight, and he probably would not have achieved as much without his confrontational tactics, especially his tweets, which overcome the media filter (see #5, below). But his style does grate on some voters, who cannot see past the things Trump has said (or is sometimes falsely alleged to have said). Obama was also hostile to opponents, and it motivated Republicans to rebuke him at the polls. Democrats — and some suburban Republicans — are eager to send a message back to Trump this fall.

5. Media war. “Bias” does not begin to describe the media’s unrelenting campaign to topple this president. The press has spent the better part of two years on a conspiracy theory of Russian collusion for which there remains no evidence. That has encouraged the opposition to expect Trump’s imminent resignation or eventual impeachment, and to hold out against any compromise on major issues facing the country. The media’s anti-Trump crusade has also hurt Republican candidates in down-ticket races nationwide.

Of the five factors above, there is only one that Republicans can do anything about — at least in time for Election Day: namely, the border wall. That is why Trump is talking about a shutdown. Indeed, the prospect of a Blue Wave might embolden him to carry out his threat: if Democrats seem likely to win anyway, why not fight as hard as possible now for a wall that will be impossible next year? A shutdown fight could also invigorate the Republican base (see #1) — especially if Trump wins the funding he demands.

Republicans have one other ace up their sleeves: Nancy Pelosi. The House Minority Leader insists that she will run for Speaker again if Democrats win a majority. But every Democrat who has won a special election in the past several months has done so while promising not to vote for her.

Making the 2018 midterms about stopping Pelosi will probably not, by itself, be enough for Republicans to hang onto power. But it will help — and right now, it looks like Republicans will need all the help they can get.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He is a winner of the 2018 Robert Novak Journalism Alumni Fellowship. He is also the co-author of How Trump Won: The Inside Story of a Revolution, which is available from Regnery. Follow him on Twitter at @joelpollak.