It sounds like the beginning of a joke: Two libertarians and a corporate lobbyist walk into a social hall . . .

On Wednesday, though, this very scenario happened in Ashland, Va. Three Republican politicians shared a stage, and one of these things was not like the others.

There was Rand Paul, ophthalmologist turned senator and 2016 presidential hopeful, a tea party darling who would like to strip big government right down to its skivvies.

There, too, was David Brat, seminarian cum economics professor who gained national fame for defeating Eric Cantor in a primary by portraying the House majority leader as a Washington insider who was too liberal on immigration. The longtime Brat friend who introduced him to the crowd said that “he is divinely inspired to represent the entire 7th District.”

And finally, there was Senate candidate Ed Gillespie, longtime political operative and founder of an eponymous lobbying firm that represented, among others, Enron. He’s more the embodiment of the Washington establishment than Cantor ever was.

Here’s the punch line: The three got along just fine. “I see unity,” proclaimed Paul.

Of course he did. The trio went to painful lengths to cover over divisions.

“One thing I love about Dave is he’s for term limits, and so am I,” Paul said of Brat.

At this, Gillespie pointed to himself.

“And Ed as well,” Paul added, caught off-guard. If Gillespie supports term limits, he’s been awfully silent about it. His spokesman didn’t respond to questions about when he had taken such a position.

The men papered over their differences because of one overriding and unifying goal: to inflict as much damage as possible on President Obama and his agenda on Election Day.

“People ask me what’s the worst thing Obama’s done, and it’s a long list,” Paul said.

“Impeach Obama!” somebody in the audience shouted.

“It’s the president’s absolute disregard for the Constitution,” Paul went on. “It’s the usurpation of power.”

“Treason!” somebody else in the audience shouted. Brat smiled; the others ignored the accusation.

Paul went on to accuse Obama of “a form of tyranny,” adding, “This is everything we must rise up against.”

That antipathy toward the unpopular president more than any single issue is what is propelling Republicans to likely gains in November. A CBS News poll found that 31 percent of registered voters see the election as a way to raise objection to Obama, while only 18 percent see it as a way to affirm Obama. That’s nearly as bad as it was for George W. Bush in 2006 before major Democratic gains.

Republicans are so confident of anti-Obama sentiments that they aren’t making an effort to present an alternative agenda, the way they did with 1994’s “Contract With America” or 2010’s “Pledge to America.” The Republican National Committee drafted only vaguely worded “principles” (“Our Constitution should be preserved, valued and honored”).

Wednesday’s event for Brat (who is likely to win) and Gillespie (who is not) required particular agility by the performers to promote togetherness. Brat won his primary by claiming Cantor supported amnesty; Gillespie had been a promoter of comprehensive immigration reform. Paul has made it his priority to open the Republican Party to minorities and youths, but of the few hundred people in the hall in Ashland, only two non-white faces were visible among the older crowd — and the event was to promote the election of the man who had ousted the lone Republican Jew in Congress.

Gillespie, in pinstriped suit-pants over his loafers, wore a frozen grin as Brat promised “much less of the crony Wall Street connection up there in D.C.” Gillespie, a political appointee in Bush’s White House, seemed to distance himself from himself when he vowed to keep “political appointees in Washington, D.C.,” out of health-care decisions. So eager were candidates and attendees for unity that they even applauded Paul, dressed in blue jeans and cowboy boots, when he spoke out for shorter drug sentences.

Their speeches included scattershot references to Obamacare, regulations, taxes, energy, school choice, veterans, the military, China, judges and Ebola. But promises to block the other side’s agenda inspired the most enthusiasm. Based on the crowd reaction, Brat’s best case for Gillespie was that “we need him to be a check on all of President Obama’s destructive policies.”

Gillespie’s best case for himself, measured by the standing ovation, was that he could “make Harry Reid the former Senate majority leader” — and stop the Democratic incumbent, Mark Warner, from voting for Obama’s agenda.

“We just saw recently President Obama said basically that his policies are on the ballot this year — every single one of them,” he said.

Saying no does not an agenda make, but for Republicans in 2014, it may be enough.

Twitter: @Milbank

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