LOUISVILLE, Ky. – Rand Paul, the Tea Party-backed Republican nominee for the Senate, sent a thank-you note on Saturday night to South Carolina Sen. Jim DeMint, a father of the Tea Party movement, who was coming to a rally for him in northern Kentucky.

"I smile when I think of what we can do together in the Senate if the people send me," Paul wrote.

DeMint related the note to the crowd of 300 people at the evening rally, in Erlanger, and said he himself smiled at the thought of "not just us two but eight or 10 senators" being elected, going up against the Republican establishment and pushing for the Tea Party goals of limited government.

But DeMint’s smile may have vanished by morning. During a nationally televised debate on Fox News Sunday, Paul said that if he were elected to the Senate, he would support Sen. Mitch McConnell, R-Ky., to keep his job as Republican leader.

Pressed to say whether he would choose him over DeMint, Paul said he would vote for whomever Republicans chose as their leader and he assumed it would be McConnell.

It was one more sign that no matter how devoted Paul is to Tea Party principles and goals, he may be forced to yield periodically to some realities of the old-school politics that he denounces.

This also occurred last month, when McConnell set up a fundraiser in Washington for Paul with several Republican senators who, like McConnell, had supported the $700 billion bank bailout in 2008. During the primary, Paul said he would not accept donations from anyone who had done so.

With the election just a month away, Paul’s earlier wide lead in the polls over Jack Conway, his Democratic opponent, has narrowed but he still appears ahead. And Paul may be acting a bit more cautiously these days to hold on to his lead, which is par for the course for many candidates after they emerge from a party primary and face the broader electorate.

"His approach has changed," said Trey Grayson, the secretary of state, who lost to Paul in the primary. "He’s acting more like an incumbent. His tone is designed more for a general election audience and swing voters."

But, Grayson quickly added, Paul still gets across his points. "He still, at the end of the day, talks about shrinking the size of the government," Grayson said. "Those things haven’t changed, and that’s why he’s ahead in the polls."

During the spring primary, Paul invariably opened his speeches by declaring that "a Tea Party tidal wave is coming." His "randslide" win of the Republican nomination was the movement’s first major success on the national stage.

Now, his references to the Tea Party are fewer and farther between. On a trip last week through Eastern Kentucky, the movement’s trademark yellow "Don’t Tread on Me" flags were gone. Paul did not sound his earlier battle cry that he would shut down Congress for a week if it failed to amend the Constitution to require a balanced budget. In fact, he did not mention the Tea Party at all.

Almost inconspicuous in a dark blue button-down shirt and cotton pants, Rand began his short speech in London by reciting in a soft voice the names of the other small towns he had just visited.

"I haven’t met one person on the entire trip who is in favor of President Obama or any of his policies," he said. Even Democrats, he added, "realize that this is the most anti-Kentucky, anti-coal president we’ve ever had."

He put in a slight dig at his opponent, Conway, whom he did not name and whom he rarely mentions, saying that the Democrat had once supported the cap-and-trade legislation, which is much loathed in this coal-producing state. "He was for it before he was agin’ it," Paul, who is an ophthalmologist, said.

"He’s planing off the edges," said Al Cross, director of the Institute for Rural Journalism and Community Issues at the University of Kentucky.

At Saturday’s rally, however, Paul did acknowledge the Tea Party. His campaign had bused in from Northern Kentucky several dozen members of a contingent who were having a convention nearby. Paul shared the stage with his father, Rep. Ron Paul, the Texas Republican and 2008 presidential candidate, and with DeMint. At that event, they more overtly roused Tea Party sentiment.

The Conway strategy has been to cast Paul as out of the mainstream (in one advertisement, some seniors say he is "off the wall" and question "what planet" he is from. They also portray him as being unfamiliar with the state. Indeed, Paul focuses chiefly on national issues, like the debt and spending.

But Danny Briscoe, a Democratic consultant here who is not part of the Conway campaign, said this approach had not worked so far. Paul has "managed to appear normal," Briscoe said, particularly with other controversial Tea Party-backed candidates, like Christine O’Donnell in Delaware, taking over the national stage.

Analysts here say the race appears to be Paul’s to lose. It seems he would have to make a blunder of gigantic proportions to alienate his supporters, and neither candidate appeared to make many in the debate on Sunday.

Paul said he would raise the retirement age for Social Security and Medicare – he did not say to what age – and the deductibles for Medicare, casting these steps as the responsible approach. Conway seemed more exposed on the question of whether he had once supported the cap-and-trade legislation, which he now opposes. He said he had not, but newspaper accounts say he did.

Paul repeatedly tried to tar Conway with President Barack Obama’s policies, and Conway stood up for some of them, including the health care law, which he said would provide 654,000 Kentuckians with health care for the first time. The candidates agreed on one thing – they both support extending the Bush administration tax cuts. Paul said he would make up the $4 trillion cost by introducing bills to reduce spending.

Conway gave Paul an opening when he said it was "a tremendous honor to be running for Wendell Ford’s senate seat," referring to the Democratic Senator who represented Kentucky for 24 years.

"I didn’t know it was Wendell Ford’s seat," Paul replied. "I thought it was the people of Kentucky’s seat." Scott Brown, the Republican insurgent, used a similar line to great effect earlier this year when he won the Senate seat long held by Democrat Edward M. Kennedy in Massachusetts.

One poll puts Paul and Conway in a statistical dead heat. Conway has pointed to that as he seeks to fire up voters.

"You’re looking at all that stands between Rand Paul and the United States Senate," Conway declared on Friday at a Democratic Women’s Club of Kentucky luncheon. "Does that bring it home for you?"

While the women applauded him, they treated him almost like a bystander in the race. Susanna French, the club president, introduced him by saying he could still win if he "doesn’t say a word" and lets Paul do all the talking.

Diane Wood, a retired auditor and past club president from western Kentucky, who attended the lunch, said there was "a lot of apathy" among Democrats.

"The Tea Party is very appealing to people in my end of the state," she said. "When people are against something, that always motivates them more to come out and vote."

After a Paul rally in Laurel County, Bryan Mills, the county’s Republican chairman, said he could not imagine anything that Paul could do to lose his support. Mills, 34, quit his job in computer training after Paul won the primary to oversee his campaign in the region.

"Dr. Paul has the wind to his back right now," Mills said, adding that the denunciations of him as "an extremist or a kook" only inspire his supporters.

"If someone is constantly telling you you’re wrong and the guy you’re supporting is nuts, you get angry," he said. "People dig in more because they feel like their beliefs are being attacked."

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