FRANKFORT, Ky. - The angry man of the Senate is at it again.

Republican Sen. Jim Bunning, a 78-year-old Hall of Fame pitcher, is playing hardball on Capitol Hill, single-handedly holding up a $10 billion spending bill because it would add to the deficit.

The move has forced some 2,000 federal employees into unpaid furloughs, put jobless benefits in jeopardy for millions and halted more than 40 highway projects.

Because of his ornery nature and ungovernable mouth, Bunning has come to be regarded as the crazy uncle in the Senate attic during his 11 years in Washington. And because he is retiring after this session, there isn't much anyone can do to keep him in line.

"I think the older he gets, the more cantankerous he becomes," said Kentucky Republican Larry Forgy, a two-time candidate for governor and one of Bunning's biggest admirers. "He's as tough as a pine knot. He doesn't care what they say about him."

It's not the first time Bunning has made others cringe.

Last year, he had to apologize after he predicted Supreme Court Justice Ruth Bader Ginsburg, who was diagnosed with pancreatic cancer, would be dead within a year.

During his 2004 re-election campaign, which he narrowly won, he said his Democratic opponent - Daniel Mongiardo, who is of Italian descent - looked "like one of Saddam Hussein's sons." He apologized for that, too.

Bunning also accused Mongiardo of spreading rumors that he was mentally unfit to be a senator, a charge Mongiardo denied. The Courier-Journal ran an editorial questioning Bunning's "suitability" for office and wondering whether he had "drifted into territory that indicates a serious health concern." Bunning released letters from doctors vouching for his health.

He has feuded with GOP floor leader Mitch McConnell, the other senator from his state.

Bunning has also been known to curse at reporters. On Tuesday, ABC and CNN showed video of him refusing to talk to reporters about blocking the spending bill. "Excuse me!" he snapped. "This is a senators-only elevator." ABC said he gave the finger to one of its producers.

Few people in Kentucky, where the senator has been in politics for more than 30 years, were surprised last week when he stopped legislation that would have extended funding for a variety of federal programs, including the flood insurance that many people in the nation's heartland rely on when the spring flood season arrives.

"He's cruel," said Louisville resident George Boyd, who lost his job a year ago and could be affected by the impasse. "He's heartless. He doesn't think about the needs of other people."

Bunning is so toxic that Republican leaders pushed him to retire when his second term is up at the end of the year.

At one point, he threatened to sue the party's national campaign arm if it backed a primary challenger. But in July he relented and dropped his re-election bid, accusing his GOP colleagues of doing "everything in their power to dry up my fundraising."

University of Kentucky political scientist Donald Gross speculated that Bunning's effort to hold up the spending bill might reflect frustration that after two terms he has no notable legislative legacy and has essentially been forced into retirement.

"He's always been an argumentative type of person, testy," Gross said. "This may be his last hurrah, his last chance to take a slap at people before he leaves."

During his days with the Detroit Tigers and Philadelphia Phillies, for whom he pitched a perfect game in 1964, the right-hander who faced the likes of Ted Williams, Mickey Mantle and Roger Maris never hesitated to bean batters. He was elected to the Hall of Fame in 1996, the first pitcher to record 100 wins and 1,000 strikeouts in both the American and National Leagues. He is also a Xavier University-educated economist who has taken a hard line on fiscal issues.

He has been holding up the spending bill since Thursday, saying he objects because it requires borrowing money. Bunning proposed to pay for the extension with unspent money from last year's big economic recovery package, but Democrats objected.

By the Senate's rules, that single objection was enough to block the bill, at least temporarily.

Democrats have bashed him for stopping a measure of vital importance to down-on-their-luck Americans, and White House spokesman Robert Gibbs said Tuesday: "I don't know how you negotiate with the irrational."

Bunning refused to budge, to the increasing discomfort of some fellow Republicans.

"He's hurting the American people," Sen. Susan Collins, R-Maine, said when asked Tuesday if Bunning was hurting the Republican Party.

He has also become fodder for late-night comedians, with Jon Stewart of Comedy Central's "The Daily Show" calling Bunning a "cranky obstructionist" and joking that he is "leaving the Senate to spend more time obstructing his family's progress."

But Forgy, of the Kentucky GOP, said Bunning should be praised: "It's the equivalent of hitting the mule between the eyes with a two-by-four to get its attention. He is drawing attention to an issue, and if he has to draw criticism to himself in the process, he's willing to do that."