WASHINGTON (AP) — Republican Marco Rubio’s potential defection over a tax credit for low-income parents put a speed bump into GOP leaders’ drive to push their big tax package through the Senate, but it’s a complication that’s likely to be resolved.

The Florida senator declared Thursday that he’ll vote against the $1.5 trillion bill unless House and Senate negotiators expand the tax credit that low-income Americans can claim for their children.

That puts the Republicans’ razor-thin margin in the Senate closer to the edge. The GOP leaders are straining to muscle the bill through Congress next week, handing President Donald Trump his first major legislative victory by Christmas.
Senate Republicans could still pass the package without Rubio’s vote, but they would be cutting it extremely close. An original version was approved 51-49 — with Rubio’s support. The co-sponsor of Rubio’s proposed change, Republican Sen. Mike Lee of Utah, is undecided on the overall bill and is pushing to make the credit as generous as possible, said Lee spokesman Conn Carroll.

The Senate turmoil erupted the same day that a key faction of House Republicans came out in favor of the bill, boosting its chances. Members of the conservative House Freedom Caucus predicted the vast majority of their members would support the package.

The up-and-down turns came a day after House and Senate Republican leaders forged an agreement in principle on the most sweeping overhaul of the nation’s tax laws in more than 30 years. The package would give generous tax cuts to corporations and the wealthiest Americans, and more modest tax cuts to low- and middle-income families.

Republican leaders predicted swift passage next week, sending the bill to Trump for his signature.

At the White House, Trump said he was confident that Rubio will get onboard.

“He’s really been a great guy and very supportive. I think that Sen. Rubio will be there,” said Trump, who belittled Rubio during the 2016 GOP presidential primaries, calling him “little Marco.”

The tax package would double the per-child tax credit from $1,000 to $2,000. The bill makes a portion of the credit — $1,100 — available to families even if they owe no income tax. They would receive the money in the form of a tax refund, which is why it’s called a “refundable” tax credit. Rubio wants to increase this amount but wouldn’t say by how much.