WASHINGTON — The barbs are personal, the differences are multiplying among Republicans, a party divided over spending, foreign policy, a willingness to risk a government shutdown in order to defund the health care law and more.

“I didn’t start this one, and I don’t plan on starting things by criticizing other Republicans,” Sen. Rand Paul of Kentucky said recently as he and New Jersey Gov. Chris Christie likened one another to various cuts of a butchered pig.

“But if they want to make me the target, they will get it back in spades.”

No matter who started it, in the past few months, one Republican called others “wacko birds,” another said some of the party’s lawmakers were “stale and moss-covered” and a third suggested one member of the GOP was a tool of the White House.

A recent flare-up over defunding the health law prompted Texas Sen. Ted Cruz to question the political manhood of fellow Republicans unwilling to risk closing down the government over the future of “Obamacare,” as GOP critics call the law they want to repeal.

Not all the disagreements are dipped in acrimony. Some are re-emerging after the party papered over its differences in an unsuccessful campaign to defeat President Barack Obama last year. This spring, 14 Senate Republicans supported legislation that included a chance at citizenship for millions living in the country illegally. The other 32 opposed it, including the entire top leadership.

In some cases, though, policy or strategic differences are overshadowed as Republicans simply call one another names, a type of clash that frequently pits newer, tea party-backed lawmakers against more experienced conservatives.

Two months ago, Sen. John McCain of Arizona likened Cruz, Paul and others to “wacko birds” for their style of confrontational politics.

Rep. Justin Amash of Michigan responded from across the Capitol. “Bravo, senator. You got us. Did you come up with that at #DinnerWithBarack?” he tweeted, a suggestion that McCain was parroting a line he had heard at the White House.

Paul responded a while later to McCain. “The GOP of old has grown stale and moss-covered. I don’t think we need to name any names, do we?” he told an audience of conservatives.

Other, more recent clashes appear born of political calculations and fall just shy of personal criticism.

Cruz, along with Sens. Mike Lee of Utah and Marco Rubio of Florida, recently urged Republicans to swear off voting for any year-end spending bill that includes money for the health law.

Others countered that the result could be a partial shutdown of the government and a political windfall for Democrats.

“I think it’s the dumbest idea I’ve ever heard,” said Sen. Richard Burr, R-N.C.

Burr was in the House nearly two decades ago when Republicans threatened they would shut down the government in hopes of winning spending concessions from President Bill Clinton. They followed through but were forced into a retreat as the White House held firm and public opinion turned against them.

All Republicans say they want to repeal the health law, but the tea party-backed campaign has thrust some lawmakers into difficult positions as they juggle competing political imperatives.

Differences among rank-and-file lawmakers make for bipartisan agreements, but they also can make it hard for party leaders to negotiate effectively with the White House and Democrats.

Among Republicans, disagreements over foreign policy and national security are “normal, kind of an ideological contest that’s been with the party in the 20th century and will be in the 21st,” said McCain.