E. W. Jackson, from left, responds to a question as Jamie Radtke, Bob Marshall and George Allen (not shown) listen May 25 during their third and final Republican primary debate for U.S. Senate in Virginia, at the Fairview Park Marriott in Falls Church. (Richard A. Lipski/FOR THE WASHINGTON POST)

The four Virginia Republicans running for U.S. Senate squared off Friday in their third and final debate before the June 12 primary, lobbing most of their criticism at President Obama and former governor Timothy M. Kaine, the Democrat each hopes to take on in November.

While a couple of the underdogs in the race took shots at front-runner George Allen, they mostly stuck to the issues, from well-worn subjects such as “Obamacare,” which they all oppose, to the newly hot topic of gay judges, on which there were some differences.

Allen, a former senator and governor, is seeking the nomination along with three distant rivals: Del. Robert G. Marshall (R-Prince William), tea party activist Jamie Radtke and Chesapeake minister E.W. Jackson.

In the hour-long debate, all four spoke of the election as coming at a pivotal moment for the United States, which they described as on its way to fiscal and social ruin and desperately in need of stronger leadership in Washington.

“I am not an African American. I am an American,” Jackson declared, prompting hearty applause from the mostly white audience of 500 that had elected to kick off Memorial Day weekend with an evening in a Falls Church hotel ballroom. “It is time to end the tenure of King Barack.”

Later, Allen said that this election “is our generation’s rendezvous with destiny. And freedom hangs in the balance.”

A recent Washington Post poll showed Allen getting 62 percent of the vote among likely GOP primary voters. Marshall was next, with 12 percent, and Radtke and Jackson had 5 percent and 3 percent, respectively.

The winner of the primary will face Kaine in November. He has no opposition for the Democratic Senate nomination. The race for the seat being vacated by retiring Sen. James Webb (D) is expected to help determine the balance of power in the Senate.

In previous debates, Allen’s rivals have criticized his record as a single-term senator and as governor, while Allen has mostly focused on Kaine’s stints as governor and Democratic National Committee chairman.

Radtke, who had been the most aggressive against Allen, launched radio ads this week that labeled him as a big spender who as senator went along with the ways of Washington instead of challenging them. But she only took a few swipes at him Friday.

“This moment in time does not call for politics as usual,” she said.

Marshall needled Allen when the topic turned to gay judges, suggesting that the former governor was tiptoeing around an issue that the delegate had championed in Richmond a week earlier against the wishes of party leaders weary of social issues in the General Assembly.

About 10 days earlier, Marshall had successfully pushed the General Assembly to block the nomination of a gay Richmond prosecutor for a city judgeship. Marshall contended that Tracy Thorne-Begland, who came out as gay as a naval officer 20 years ago on “Nightline,” was unfit for the bench because he had challenged the military’s ban on gays openly serving in the military, advocated for gay marriage and lives with a partner with whom he is raising twins.

Marshall said his actions amounted to military insubordination and a challenge to the state constitution, which bans gay marriage and civil unions. At a Richmond tea party event earlier Friday, Marshall also said homosexuality “cuts your life by about 20 years,” the Richmond Times-Dispatch reported.

“When you are in the caucus and everybody’s glaring at you . . . you’ve got to have a little bit of guts,” Marshall said during the debate. “I went to a thug high school.”

When Allen was asked for his position on the nomination, he once again struck a middle-of-the-road stance, saying he opposed both activist judges and anti-gay discrimination in judicial appointments.

While Jackson and Allen had issued statements on the Thorne-Begland matter last week, ­Radtke ducked the issue until the debate. Debate moderator Bob Holsworth, who presented questions submitted through the Republican Party of Virginia’s Facebook page, asked Radtke about Thorne-Begland first.

“Oh, Bob,” she reacted, to laughter. “I think it’s interesting that the media wants to make this a divisive issue because they can’t really talk about the issues.”

But she went on to say: “The biggest threat that we have in this country is activist judges.”

Holsworth, a former Virginia Commonwealth University political scientist, asked the candidates whose side they were on in the case, Marshall’s or that of Thorne-Begland’s House sponsor, Del. G. Manoli Loupassi (R-Richmond).

“I’m on the Lord’s side,” Jackson responded. “We don’t need activist judges with a radical agenda. . . . I [would] put a hold on any judge who does not believe in sanctity of life and doesn’t believe that the family is one man, one woman, married under God.”

As in previous debates, Allen offered up the essence of his stump speech, stressing the need for new energy sources, smaller government and less regulation. He tried to present himself as the sunny candidate among the bunch.

“And keep smiling,” he said at one point, “ because we’re helping our fellow Americans catch their dreams.”