St. Paul, Minn. ? Republicans assailed Barack Obama as the most liberal, least experienced White House nominee in history Tuesday night and enthusiastically extolled their own man, John McCain, as “ready to lead this nation.” Delegates at the GOP National Convention rallied behind running mate Sarah Palin in the face of fresh controversy.

“Country matters more than party,” declared Sen. Joseph Lieberman, the 2000 Democratic presidential nominee, making a prime time appeal from the Republicans’ podium to disaffected Democrats and independents. Delegates booed heartily when he said Obama had voted to cut off funding “for our troops on the ground” in Iraq.

A parade of speakers, led by President Bush, hailed McCain, praising him as a war hero who endured years of torture in Vietnam and decades later risked his White House ambitions to support an unpopular Iraq war.

The Republican nominee-in-waiting campaigned in Pennsylvania and Ohio during the day, slowly making his way toward the convention city where the 72-year-old Arizona senator will deliver his formal acceptance speech on Thursday night.

Hundreds of miles to the west, in St. Paul, about two dozen men who were Vietnam prisoners with him a generation ago sparked chants of “USA, USA” when they were introduced to the delegates.

Bush, an unpopular president relegated to a minor role at the convention, reprised the national security themes that propelled him to a second term as he spoke – briefly, by satellite from the White House. “We need a president who understands the lessons of Sept. 11, 2001,” he said. “That to protect America, we must stay on offense, stop attacks before they happen and not wait to be hit again. The man we need is John McCain.”

Former Tennessee Sen. Fred Thompson drew some of the loudest cheers of the night as he scoffed at Obama, the 47-year-old Illinois senator who is seeking to become the first black president.

“Democrats present a history-making nominee for president. History-making in that he is the most liberal, most inexperienced nominee ever to run for president,” Thompson said as delegates roared their agreement.

Like Lieberman, Thompson described Palin as a political maverick in the McCain mold.

Thompson delivered a particularly sharp defense of the Alaska governor. She is “from a small town, with small-town values, but that’s not good enough for those folks who are attacking her and her family.”

He said McCain’s decision to place her on the ticket “has the other side and their friends in the media in a state of panic.”

Other Republicans – delegates and luminaries alike – also defended Palin, who disclosed on Monday that her 17-year-old unmarried daughter is pregnant. In addition, a lawyer has been hired to represent the governor in an ethics-related controversy back home in Alaska.

Conservatives, slow to warm to McCain even after he clinched the nomination last spring, were particularly supportive.

“I haven’t seen anything that comes out about her that in any way troubles me or shakes my confidence in her,” said former Arkansas Gov. Mike Huckabee, who ran unsuccessfully for the party’s presidential nomination this year.

“All it has done for me is say she is a human person with a real family.”

And Ron Nehring, chairman of the California state party, said video footage of Palin on a firing range was helping her cause.

“The reports I’m getting back is that every time they show that footage we get 1,000 precinct walkers from the NRA,” he told members of his state’s delegation, to laughter. “She cuts taxes and shoots moose. That’s Gov. Palin,” Nehring said.