By David Morgan

WASHINGTON (Reuters) – Republicans in Congress have until the end of May to negotiate provisions of an infrastructure bill before Democrats opt to move sweeping legislation on their own, one of U.S. President Joe Biden’s closest Senate allies predicted on Wednesday.

Democratic Senator Chris Coons of Biden’s home state of Delaware said several senior Senate Republicans had privately signaled they would support a package of up to $1 trillion that targets roads, bridges and other typical infrastructure areas and includes some tax increases to pay for legislation.

Biden has proposed a more sweeping $2 trillion infrastructure package, which invests in traditional projects but also seeks to change the course of the U.S. economy by addressing climate change and boosting human services such as elder care.

The president and his Democratic allies, who narrowly control both houses of Congress, have insisted that they want Republican support for the package but will not wait long before deciding whether to move forward on their own.

“I believe that President Biden is open to spending the next month negotiating what the possibility is,” Coons told Punchbowl News in an interview. He said he spoke to the president earlier this week.

If no clear deal exists by the May 31 Memorial Day holiday, Coons added, “I think Democrats just roll it up into a big package and move it.”

Biden is expected to meet with a bipartisan group of lawmakers on infrastructure next week, said White House spokeswoman Jen Psaki.

Coons said talks with “several fairly seasoned senior Republicans” suggest bipartisan support for a narrower bill that could be funded partially by higher gasoline taxes and a new fee for electric vehicles to be dedicated to road infrastructure.

But the president’s larger plan faces determined opposition from Republicans including Senate Minority Leader Mitch McConnell, who describes the Biden package as “a Trojan horse” for tax hikes and unnecessary spending.

“There’s broad bipartisan support for tackling the infrastructure issue. But it depends on what your definition is,” McConnell told a Wednesday news conference in his home state of Kentucky.

“Infrastructure is roads, is bridges. It’s broadband. But beyond that, they’ve thrown everything but the kitchen sink into it,” he said.

Republican opposition raises the odds Democrats will use a maneuver called reconciliation to pass a package with just their own votes. Democrats control half the 100 seats in the Senate with Kamala Harris, Biden’s vice president, the tie-breaking 51st vote.

(Reporting by David Morgan; Editing by Scott Malone and Howard Goller