On Monday, House Majority Leader Kevin McCarthy put conservatives on notice that if they force Republicans to indulge their appetite for maximal confrontation with President Obama, it will cost them the next presidency.

“If we don’t capture the House stronger, and the Senate, and prove we could govern, there won’t be a Republican president in 2016,” he told Politico.

His sensible plan to avoid this outcome is to eliminate “cliffs”—big statutory deadlines, like the debt limit and the expiration of government funding, that Republicans have run up against in recent years to demand ransoms from Democrats and President Obama. To fund the government, increase the debt limit, and then fight policy battles on the merits.

Conservatives don’t really want to hear that message, though, so RNC Chairman Reince Priebus is essentially telling them to ignore it, specifically with respect to Obama’s anticipated immigration deportation relief program.

“While I can’t speak for the legislature, I’m very confident we will stop that,” Priebus told conservative activists Monday evening. “We will do everything we can to make sure it doesn’t happen: Defunding, going to court, injunction. You name it. It’s wrong. It's illegal. And for so many reasons, and just the basic fabric of this country, we can’t allow it to happen and we won’t let it happen.”

Other Republicans, including Senate Minority Leader Mitch McConnell, have promised to use Congress’ spending power—which includes the power to shut down the government—to seek concessions from Obama in arenas like health reform and environmental regulation. McCarthy’s proposed return to normalcy already had powerful skeptics. But Priebus set a new bar by promising not just episodic confrontation but victory.

This is a promise he doesn’t have the power to keep. When he says he “can’t speak for the legislature” what he means is “blame them if my prediction doesn’t come to pass.” If between now and then his rousing call to arms motivates Republican base voters to the polls, he might see it as a promise worth making and breaking.

But we should be clear about what the promise he’s making entails.

Priebus referenced the courts in passing as a potential firewall against Obama’s executive actions. But as it happens, we’ve just learned that courts are neither politically nor procedurally viable tools in these separation-of-powers fights.

Earlier this year, before it degenerated into a political liability for Republicans, House Speaker John Boehner and his staff took his plan to sue President Obama pretty seriously. The primary goal was to avoid getting dragged into an impeachment fight ahead of the election, which in one sense meant staving off a conservative rebellion through September. There he succeeded. But the secondary goal was to avoid embarrassment by addressing the legal complications with great precision. Boehner needed first to gain standing, and then to make a compelling case that the administration had actually violated the law. For that reason he didn’t just toss every executive action Republicans disliked on to the bill of particulars, but settled on a single complaint. He chose to sue Obama for unilaterally delaying the Affordable Care Act’s employer mandate because his lawyers believed it was the administration’s most clear-cut violation of the law.

But they were probably wrong. Obama just isn’t as over-reaching as Republicans have convinced themselves he is. That’s a happy outcome for Boehner because it allows him to shelve the lawsuit for the time being: It turns out suing Obama doesn’t satisfy hardline conservatives, but it makes Democrats pretty angry. This brings us back to immigration, and Priebus’s promise to the Tea Party. As a legal matter, Obama’s existing deferred action program probably stands on firmer legal footing than his employer mandate delay. Extending that program won’t necessarily implicate other legal issues. But even if it did, Republican leaders will be reluctant to sue Obama to force him to deport as many low-priority offenders as possible. And conservatives will be even less satisfied with a lawsuit if the issue at stake is "amnesty," especially if it arises immediately after Republicans win control of the Senate. They’ll demand quick blood.

So the courts aren’t really an option for Priebus. His comments to conservatives only make sense as a promise of high-wattage confrontation—over funding the government, increasing the debt limit, impeachment—or as outright deception.