Republicans are trying to get Americans excited about their tax bill, but it’s a tough sell.

Even President Donald Trump tossed out prepared remarks on taxes at a roundtable in West Virginia this week. Holding them up, he said, “That would’ve been a little boring,” then tossed them away.

Trump’s quip got laughs, but congressional Republicans who are trying to win in 2018 on a tax cuts message may not find it funny.

Their list of major legislative accomplishments is shorter than they anticipated: They’ve got tax cuts and a conservative Supreme Court justice. While Republicans’ tax plan is more popular today than it was when Trump signed it into law, Democrats continue to sweep once safely red races. Republicans are growing increasingly concerned that tax cuts might not be enough.

“It’s all they’ve got. It’s a one-trick pony,” said Senate Minority Whip Dick Durbin (D-IL) told Politico. “It’s the tax pony, and that’s the only horse they have to ride.”

Traditional conservatives are quick to maintain tax cuts are a winning message. Washington Rep. Cathy McMorris Rodgers, who leads the House Republican conference, said the country hasn’t yet experienced the “full momentum of tax reform” after Republicans lost a special election in a Trump +20 district in Pennsylvania.

“You should not undersell giving almost the entire country a tax cut,” Guy Benson, a conservative pundit and editor at Town Hall, told Vox. “The law is working, and you can use the law as a springboard of talking about what is working.”

But in the field, we’ve seen a different kind of messaging crisis management. In the Trump era of Republican politics, the backup plan to an ineffective economic message has been to wage a culture war.

Fearmongering and race-baiting about MS-13 gangs, Confederate statues, and sanctuary cities are divisive messages that worked for Trump. When polls tighten, we’ve seen Republicans turn to these messages in the final weeks of the race. It’s just not clear it will stanch the bleeding.

The retreat to a race war hasn’t worked

Republicans had an early test of their 2018 messaging in early March. A special election in Pennsylvania’s 18th District — the first after Trump signed the GOP tax cuts into law — was supposed to be a safe Republican race. It was a rural, very white district that Trump had won by 20 points. In spite of all that, Democrat Conor Lamb prevailed.

The loss was interpreted as a major wake-up call for a party that was dead set on putting tax cuts front and center. At the beginning of February, almost two-thirds of GOP ads in the race were about the Republican tax law, according to a Politico analysis. Outside groups spent more than $7 million largely on that message.

Trump came to the state for a conveniently located GOP tax rally in western Pennsylvania in January, and the Republican candidate, Rick Saccone — a man who touted himself as “Trump before Trump was Trump” — defended the tax cuts in a debate against his Democratic opponent, and eventual election winner, Lamb.

When it became clear that it wasn’t enough to secure the lead, Republicans made a sharp pivot; Trump’s March rally for Saccone called on Congress to defund so-called sanctuary cities. By Election Day, the same group’s campaign for Saccone had pivoted sharply to decrying sanctuary cities, as Politico reported:

Since the beginning of March, tax ads have been essentially non-existent. Only two are on the air now — one from the pro-Trump super PAC America First Action which briefly mentions the tax law, and a radio ad from a progressive group attacking Saccone for supporting the law.

It didn’t work. Saccone “backpedaled into cultural issues, and it looked desperate,” Benson said.

But Saccone isn’t the only candidate who has tried the racial attacks strategy. Republican gubernatorial candidate Ed Gillespie failed to mobilize GOP voters in Virginia last November, with campaign ads that tried to pick up on the white supremacist rally in Charlottesville, Virginia, and gang violence. Democrat Ralph Northam’s win was in part attributable to a notable turnout of African-American voters.

Of course, the race baiting has had some successes. Republicans have used the culture wars as their closing argument time and time again. The primaries are rife with nativist sentiment. Kelli Ward, the far-right senatorial candidate in Arizona, ousted incumbent Sen. Jeff Flake from the Republican primary race with a Trumpian “America First” message only to be challenged by Joe Arpaio, the infamous former sheriff who called for detaining people based only on suspicions of their immigration status.

But it’s not at all clear this can work in a general election. What animates a Republican base might only set up the party for failure against energized Democrats.

Trying to be Trump is risky — and often fails

Republicans have a lot of excuses for their losses in Virginia and Pennsylvania: Virginia was a blue state anyway, Saccone was a bad candidate, taxes were a bad strategy in that rural Pennsylvania district in the first place, and Lamb didn’t have a primary challenger.

But there’s another explanation, laid out here by Vox’s Jane Coaston:

The problem for Republicans is that the Trump approach isn’t a replicable model for success. Trump’s scandals are, instead, dragging down the popularity of just about every other figure within the Republican orbit — making it less likely voters would vote for any Republican at all. Republicans in Virginia and Alabama have attempted to take on the Trumpist mantle this year but lost, even in deep-red districts.

In other words, Trumpism only works for Trump.

What we have seen is that the strategy to retreat to cultural wars — the rhetoric that was largely attributed to Trump’s political success — has only opened more doors for Democrats in down-ballot races.

“When you have a really strong candidate with a really strong profile that appeals to a wide swath of the electorate, it’s not credible when you try to convince people that they are a facial tattoo artist,” one Democratic operative said.

After all, the so-called blue wave is happening for a reason.

“They have to be really careful about this. [Republicans’] tried-and-true playbook created this national backlash and an incredibly unpopular president,” the campaign operative said.