Yuri Gripas / Reuters

Updated on December 20 at 2:05 p.m. ET

President Trump has spent months exhorting Republican lawmakers to send him a tax-cut bill in time for Christmas—a $1.5 trillion stocking-stuffer for businesses and families. And on Wednesday afternoon, Congress delivered, as the House approved final passage of the GOP’s top legislative priority.

But despite Trump’s impatience for tax cuts, he might not actually sign the landmark bill into law right away, White House advisers said. In fact, Trump might wait until the new year, pushing the outer boundary of the 10 days the Constitution gives the president to affix his signature to legislation passed by Congress.

The reason for the possible delay involves a complicated bit of legislative gamesmanship. Under a 2010 “pay-as-you-go” law requiring Congress to offset any new spending or lower taxes, the $1.5 trillion bill would trigger automatic cuts to Medicare and other programs—across-the-board reductions that Republicans don’t want to be responsible for letting take effect. By waiting until the calendar turns to 2018 to formally enact the tax bill, Trump would push the automatic spending cuts to 2019 and buy Congress another year to waive them.

Congress has repeatedly—and usually routinely—passed legislation to prevent similar cuts in prior years, and Republicans are hoping Democrats will join them in doing so again in the next few days. “Just as we have done in the past, we need to pass a routine ‘Pay-Go’ waiver to avoid a draconian sequester that none of my colleagues want to see take effect,” Senate Majority Leader Mitch McConnell said on Wednesday morning, just a few hours after Republicans passed the tax bill setting those very cuts in motion. “Americans are counting on us not to inflict harmful cuts on Medicare and other essential operations.”

McConnell is right in one respect: Neither Democrats nor Republicans want the automatic Medicare cuts to happen. But having watched the GOP jam their tax bill through on a party-line vote, Democrats are in no mood to help Republicans wriggle out of a mess they created. Their votes are needed because Republicans cannot circumvent a Senate filibuster to waive the spending cuts in the same way they did to pass the tax cuts. In the House, Democrats already warned GOP leaders that if they want their votes to waive the Medicare cuts, they’ll have to make other concessions, like restoring the individual health-insurance mandate that is set to end in 2019 under the Republican tax bill. “I think the president will be anxious to sign the bill,” a senior administration official, speaking on the condition of anonymity, told reporters on a conference call shortly after the final House vote on Wednesday. The official noted that it may take Congress a few days to formally “enroll” the bill and deliver it to the White House. “We expect Pay-Go to get resolved,” the official said.

If the two parties agree to waive the cuts this week, then Trump could sign the tax bill while he’s spending Christmas at Mar-a-Lago next week, said Marc Short, the president’s director of legislative affairs. That possibility alone could push the Democrats to cooperate: They’d love to attack the image of Trump signing a tax cut benefitting the wealthy at his lush Florida vacation home.

Republicans doubt Democrats would actually vote against waiving the spending cuts, but by pushing them off until 2019, they would strip some of the Democrats’ leverage in negotiations over legislation to wrap up the year. But it would be the second awkward delay for the GOP as they put the finishing touches on their first major legislative victory of the Trump era. On Wednesday, the House was forced to vote a second time on virtually the same piece of legislation after Senate Democrats forced Republicans to remove a few minor provisions from the tax bill.

A January signing likely wouldn’t mean any delay in the implementation of the tax cuts. Trump had previously announced that the IRS would be able to change its withholding tables so that Americans see a boost in their paychecks by February. But when Republicans head to the White House on Wednesday to celebrate passage of their tax cuts with Trump, the party will be missing an important element: an actual bill to sign.

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