Will he flake? Photo: Bill Clark/CQ-Roll Call,Inc.

Ever since Senate Republicans released a tax bill that includes temporary cuts for middle-class families — and permanent ones for corporate America — GOP leaders have been talking out of both sides of their mouths.

When Democrats scream that the president’s “middle-class tax cut” would actually raise taxes on at least half of middle-income families by 2027, the Republican leadership calls malarky.

Their story goes like this: Everyone knows that those numbers are garbage, because the middle-class tax cuts will never actually expire. Republicans only phased out those tax breaks to comply with arcane budget rules — in the Senate, the tax bill can only evade a Democratic filibuster if it doesn’t add to the deficit in 2028. So, the GOP had to phase out something, just to make the math work. And the party opted to set its most popular proposals (like doubling the standard deduction and expanding the child tax credit) to expire precisely because no future administration — Democratic or Republican — will actually let that happen. In 2012, a Democratic president had a chance to let George W. Bush’s middle-class tax cuts expire. Instead, the Obama administration pushed to make them permanent. And the same show will play out in 2026. So, don’t worry. This bill isn’t actually a deficit-neutral plan to finance a corporate tax cut by soaking the middle class — it’s just a giant, unfunded, across-the-board cut loaded with budget gimmicks that mask its true price!

This is a plausible story — and, perhaps, a politically viable one. But it’s utterly incompatible with the tune that GOP leaders have been singing to their party’s few sincere deficit hawks. And those lonely fiscal scolds know they’re being lied to.

“The savings, the score, it just isn’t valid because you know that they’re not going to follow through,” Arizona senator Jeff Flake said recently. “You can’t assume that we’ll grow a backbone later. If we can’t do it now, then it’s tough to do it later.”

Flake isn’t the only Senate Republican who isn’t crazy about drastically expanding the debt that his party spent the past eight years decrying. As Politico reports:

Flake and Tennessee Sen. Bob Corker, another independent-minded Republican not running for reelection next year, have been among the most outspoken with their deficit concerns. So too, has Sen. John McCain of Arizona, a major wildcard for GOP leadership in the tax fight.

But other Republicans have gradually become more vocal about their own deficit worries, with Sens. Todd Young of Indiana and James Lankford of Oklahoma among them. GOP leaders can only lose two votes before the tax bill tanks.

“My concern is, if you slow down to actually implement it, that’s one thing,” Lankford said. “But when you assume a sunset on something that you may or may not actually sunset, you may set up other tax fights that you have in the future, or set up additional deficit.”

If McCain, Corker, and Flake want to put fiscal responsibility above upward redistribution, there’s nothing McConnell can do to stop them. The latter two senators are leaving the Senate next year, and the first is, in all likelihood, not long for this Earth. The Senate Majority Leader can’t afford to lose more than two votes. But he also can’t afford to address his deficit hawks’ substantive concerns.

Republicans are ideologically — and financially — committed to radically reducing the tax burdens of corporations, owners of “pass-through” businesses, and heirs to multimillion-dollar estates. And they are politically obligated to avoid dramatically raising taxes on middle-income people — or slashing military or entitlement spending — while doing so.

Thus, the only way for the GOP to square the needs of its donors and voters is to game the budget rules and blow up the deficit. And to do that, they’re gonna need the Senate’s handful of genuine fiscal conservatives to either keep quiet or play dumb.

In recent weeks, Corker and McCain have done the former. The Trump tax cuts will live or die on whether they’re willing to do the latter when silence ceases to be an option.