Sen. Rand Paul (R-Ky.), a favorite son of the Tea Party, wanted a seat on the Senate Budget Committee, but was passed over in favor of a more junior colleague.

The decision was made by Senate Republican leader Mitch McConnell (R-Ky.), who instead picked Sen. Kelly Ayotte (N.H.), the only member of the Senate Republican conference with less seniority than Paul. (Paul and Ayotte entered the Senate the same day, but Paul has more seniority by draw.)

A Senate GOP aide familiar with Paul's ambitions said Paul asked for the Budget seat that was to become vacant after Sen. John Ensign (R-Nev.) announced his resignation last month.

Paul's spokeswoman Moira Bagley said her boss asked for a seat on the Budget Committee at the beginning of the year. She declined, however, to comment about whether he reiterated his interest after Ensign revealed his plans to step down.

The Senate aide familiar with the behind the scenes jockeying said Paul did indeed make that request.

A second Senate aide questioned the decision: "I don't know why he'd skip Rand Paul, I don't know anyone better to have on the Budget Committee than Rand Paul."

Paul has introduced the only budget plan in Congress that would balance the budget in five years, the span set forth by the Senate GOP's proposed balanced budget amendment.

Paul is the second prominent Tea Party-affiliated senator to lose out on one of the plum assignments held by Ensign.

Sen. Jim DeMint (R-S.C.) met with McConnell earlier this month to express his interest in a seat on the Finance Committee, which Ensign vacated.

McConnell instead tapped Sen. Richard Burr (R-N.C.) to serve on Finance, a surprise pick because Burr had stated twice publicly - once through a spokeswoman - that he did not want to change his committee assignments.

Some conservatives were sharply disappointed that DeMint lost out to Burr and voiced suspicions about the North Carolina senator's apparent change of mind.

"Burr didn't show any interest in that seat and then he was interested. That raised eyebrows amongst conservatives and they thought it was an effort to get around Jim DeMint," said Brian Darling, senior fellow for government studies at The Heritage Foundation.

"There was wide expectation that DeMint was a lock for the Finance Committee," he added.

A spokesman for McConnell declined to comment.

McConnell's defenders argued that Burr should have gotten the seat over DeMint because he ranks higher on the seniority list.

But Tea Party-affiliated conservatives countered that the selection of Ayotte over Paul for the budget panel upends any rationale for picking Burr, who voted for the Wall Street bailout in 2008, over DeMint.

"For those who use the seniority argument as a blanket argument, please explain why Kelly Ayotte is on the Budget Committee and not Rand Paul?" Erick Erickson wrote Thursday on RedState.com, a conservative blog.

"This, of course, isn't a dig at Ayotte. Just pointing out that for those who are hiding behind the 'seniority' argument, you are full of b.s." Erickson wrote in a post directed at Republicans who defended the decision to put Burr on Finance.

DeMint and Paul are founders of the Senate Tea Party Caucus but neither of them have had a cozy relationship with McConnell.

DeMint clashed with McConnell in the 111th Congress over a moratorium on earmarks. DeMint wanted to halt the practice but McConnell, a longtime member of the Appropriations Committee, initially defended lawmakers' powers to direct federal spending in their home states.

DeMint defied McConnell by endorsing Paul in the 2010 Kentucky Republican primary after McConnell backed former Kentucky Secretary of State Trey Grayson. Some Republicans saw DeMint's involvement in McConnell's political backyard as a breach of Senate protocol.

Paul hasn't had the warmest friendship with McConnell since coming to Washington. Paul surprised colleagues by criticizing former Kentucky Sen. Henry Clay, one of McConnell's role models, during his maiden Senate floor speech.

"Henry Clay's life story is, at best, a mixed message," Paul said. "Henry Clay's great compromise was over slavery. One could argue that he rose above sectional strife to carve out compromise after compromise trying to ward off civil war.

"Or one could argue that his compromises were morally wrong and may have even encouraged war, that his compromises meant the acceptance during his 50 years of public life of not only slavery, but the slave trade itself," he said.

McConnell walked off the floor in the middle of that speech by Paul. An aide later said he had to attend a previously scheduled meeting.

The big spending bill passed into law with much fanfare last month will cut the deficit by $122 billion over the next decade - less than half of what top lawmakers promised at the time - the government reported Monday.

Speaker John Boehner, R-Ohio, had touted the legislation as reducing the deficit by more than $300 billion over a ten-year span. His prediction was based on an analysis by a Senate aide that the $38 billion in cuts this year would translate into $315 billion over a decade.

But the Congressional Budget Office, the closest thing to an official referee, said Monday the cuts add up to much less.

Released the same day the Treasury Department announced that the government has reached the $14.3 trillion legal limit on its ability to borrow money, the CBO study illustrates the difficulty in cutting the deficit, especially for the immediate future.

Treasury has the ability to juggle the books to avoid a default for now, but legislation to lift the so-called debt limit is going to have to include significantly greater cuts than the spending bill last month.

The budget office also said the compromise negotiated between Boehner and President Barack Obama actually increases the deficit this year by $3.2 billion, because of military spending.

At issue is a $1.2 trillion spending measure enacted after weeks of difficult talks.

Republicans had initially rammed through the House a tougher version that cut more than $60 billion this year, when compared to 2010 spending levels. But the immediate budget-cutting punch turns out to be far less, partly because the government's fiscal year is more than half over.

The final version included $25 billion in cuts to domestic agency budgets. It also contained a host of curbs to programs like federal highway funding and health care for children of lower-income families that will hardly generate any deficit savings, CBO said.

A previous CBO study had predicted that the $38 billion in cuts to non-war accounts would generate just $352 million in savings through the Sept. 30 end of the 2011 budget year. That caused consternation in GOP ranks. At one point passage of the measure appeared imperiled because of disillusionment among tea party-backed lawmakers, already disappointed the cuts weren't bigger.

That prompted Boehner to highlight a study by a Senate Budget Committee GOP staff aide, which used earlier CBO data to predict the spending bill would cut outlays by $252 billion over the decade and that the actual deficit savings would grow to $315 billion once reduced interest costs were added on.

The budget office doesn't say how much the measure would reduce interest costs.