Deficit hawks "folded like a cheap suit," during the process of finalizing the GOP's major tax overhaul legislation, CNBC's Jim Cramer said Monday.

Top Republican leaders expect passage of their tax bill this week after House and Senate Republicans reached an agreement on a joint plan Friday.

Sen. Bob Corker, a self-proclaimed deficit hawk, had voiced concerns the tax cuts would balloon the federal deficit. But the Tennessee Republican said late last week that he would vote "yes."

Corker said the final bill is "far from perfect," but decided to reconsider his stance, saying it's a "once-in-a-generation opportunity" to make U.S. businesses more competitive.

"We thought that there was this disciplined group of Republicans, who would never go for what some people are saying is a budget bust," Cramer said on "Squawk on the Street." "They folded like a cheap suit. I mean it's really rather amazing."

"They better be right," Cramer added, referring to reports the tax bill would boost the economy and increase investment in the U.S.

Cramer last week questioned whether Republicans would be able to pass their tax overhaul bill this year, or if concerns from within the party would cause them to fall short, like in their attempt to repeal Obamacare. But lawmakers on Friday were able to ease some worries.

"We're going to be looking at the election [of Trump] last year as a critical election," Cramer said Monday. The House and Senate GOP were "corralled" on the tax bill, he said.

"It's creating animal spirits like we haven't seen since the '90s," said Cramer, host of "Mad Money."