President Trump on Tuesday lashed out at Senator Rand Paul, Republican of Kentucky, for refusing to go along with a bill carrying his domestic agenda, part of an intensifying pressure campaign he has undertaken to exhort senators in his own party to quickly embrace and pass the legislation.

In a pair of social media posts, Mr. Trump claimed that Mr. Paul had little understanding of the measure, adding: “His ideas are actually crazy (losers!). The people of Kentucky can’t stand him.”

“He loves voting ‘NO’ on everything, he thinks it’s good politics, but it’s not,” Mr. Trump wrote of Mr. Paul, calling the legislation a “big WINNER!”

His broadside came as Senate Republicans began contemplating the bill, which squeaked through the House late last month over solid Democratic opposition. Even as Speaker Mike Johnson has implored senators not to make major changes that could jeopardize the measure’s chances of final approval in the House, they have made clear they intend to put their own mark on the package.

On Monday, Mr. Trump publicly urged Senate Republicans to move swiftly on the measure, touting its provisions cutting taxes, beefing up border enforcement and deportations, rolling back clean energy programs and scaling back Medicaid and food assistance, among others.

“I call on all of my Republican friends in the Senate and House to work as fast as they can to get this Bill to MY DESK before the Fourth of JULY,” Mr. Trump wrote.