COLUMBUS, Ohio – It's one of Republican presidential candidate John McCain's most surefire applause lines, a vow to veto pork barrel spending like the road and bridge projects that lawmakers hold dear.

“You will know their names. I will make them famous,” he tells his appreciative audiences.

Yet three times in recent weeks, the Republican presidential candidate supported legislation allowing thousands of these and other projects to go forward at a cost of billions of dollars. It's an awkward acknowledgment of the difficulty McCain – or any chief executive – faces in stamping out lawmakers' pet projects.

“The reality is that the Constitution invests the Congress with a great deal of power with respect to spending,” said Scott Lilly, a Democrat and former top staff aide on the House Appropriations Committee.

“Presidents almost always have programs that they want to implement that they need the cooperation of Congress to get,” Lilly said. “Presidents are generally quite willing to do that because they cover a fraction of a percent of total discretionary spending and an even smaller fraction of the overall budget.”

Rob Portman, a former Ohio congressman and budget director under President Bush, said, “The trend is in the right direction,” with the number of so-called earmarks declining in recent years. Portman, a strong supporter of McCain, added in an interview that the only sure solution would be to give the president authority to reject individual parts of the massive spending measures that Congress typically passes.

Routine spending bills often combine dozens if not hundreds of such projects, and lawmakers who are eager to protect their own are loath to vote against someone else's.

Congressional rules often prohibit votes on individual issues.

And leaders in both parties and both houses of Congress frequently combine several measures into one, calculating that the overall package will be politically difficult if not impossible to oppose.

That was the case late last month with legislation whose original purpose was to keep the government running after the Oct. 1 start of the fiscal year.

By one count, the measure included 2,322 pet projects sought by lawmakers for their home districts and states, at a cost of $6.6 billion. It also included billions of dollars in federal loan guarantees for the auto industry, and allowed a moratorium on offshore oil drilling to expire.

As a presidential candidate, McCain had to decide whether taking a stand against pork barrel spending was worth a possible government shutdown, offending auto industry workers in Michigan, Ohio, Wisconsin and elsewhere, and opposing a step he advocates to expand domestic energy production.

He skipped voting on the bill, even though he was in the Washington area at the time, and said he probably would have voted for it.

“I certainly would have done everything in my power to remove those earmarks,” he told ABC's “This Week.” “But I may have voted for it if, I probably would have ended up voting for it, but I decry a system where individual members are, are faced with taking all this unacceptable, outrageous stuff that has contributed to the largest growth in spending since the Great Society.”

In mid-September, a spokesman said McCain supported an $8 billion infusion of funding for federal highway construction, even though some of the money went to pork barrel projects the Republican presidential candidate has vowed to stamp out. According to an estimate circulated in the Senate, roughly $100,000 of the $8 billion would go to projects in Alaska, home state of McCain's running mate, Gov. Sarah Palin.

McCain supports the legislation “on the grounds that ongoing projects are threatened,” campaign spokesman Brian Rogers said in an e-mail.

Rogers added that if elected president, the Arizona senator “would be dedicated to changing the way that Washington works so that there would neither be a fear of funding earmarks – they would be gone – or a broken system that needs last-minute cash.”

Last week, the $700 billion bailout that cleared Congress with McCain's backing drew criticism from some Republicans on the grounds that the Arizona senator often cites. After the House defeated one version, Senate leaders added spending and tax breaks to make it more politically appealing.

The measure passed the Senate with ease. McCain, who had stressed the need to pass bailout legislation earlier, voted in favor of the measure, but did not speak on the Senate floor after the changes were made.

Other Republicans criticized the new measure harshly.

Rep. Steve LaTourette, R-Ohio, among the most vociferous critics, said it included tax breaks for rum, NASCAR, television and the manufacturer of wooden arrows for children.

“The pork doesn't belong in this bill. This is a financial rescue package,” he said.

LaTourette noted that 20 Republicans had sided with Democrats to make sure no votes were allowed to strip out individual items.

“As John McCain says, and sadly, for those 20 Republicans and those who aided and abetted them: We will make you famous and you shall know their names.”