ST. PAUL, Minn. — Republicans revamped their convention plans for a second day, giving a former Democrat and a television star prime-time speaking slots today while weighing President Bush’s role in the political pageantry celebrating Senator McCain’s candidacy for president.

Certain to address the storm-shortened convention were Senator Fred Thompson of Tennessee, an actor and politician and one of McCain’s rivals for the Republican nomination, and independent Senator Joe Lieberman of Connecticut, the Democrats’ vice presidential candidate in 2000 and now a McCain supporter. Republicans say the two will talk about McCain’s life and their friendship with him.

The revamped schedule suggested that convention planners were easing back into partisan politics with an appeal to independent-minded voters. Mr. Thompson is known by most voters for his portrayal of a gruff district attorney on NBC’s “Law & Order.”

It was unclear whether Mr. Thompson had replaced former Mayor Giuliani as the convention keynote and, if so, why. Convention planners said Mr. Giuliani would address the gathering in prime-time tomorrow or Thursday, though they did not know whether he would remain the keynote speaker as planned.

Whether Mr. Bush will address delegates via satellite tonight had not been decided, A White House spokeswoman, Dana Perino, said. Mr. Bush, Vice President Cheney, and others had been expected to speak last night, but the McCain campaign and convention officials agreed to trim back the politics and focus instead on fundraising for victims of Hurricane Gustav.

Hamstrung by Gustav and distracted by the revelation that McCain running mate Governor Sarah Palin’s unmarried 17-year-old daughter is pregnant, Republicans were trying to get back on track today.

Mr. Lieberman, who left the Democratic Party after losing a Senate primary, has angered many Democrats by criticizing their nominee, Senator Obama.

“I’m not going to spend any time tonight attacking Senator Obama,” Mr. Lieberman told CNN, but he added that he will explain “why I am an independent Democrat voting for Senator McCain.”

The convention seeks to reintroduce Americans to Mr. McCain and provide a high-profile introduction for Mrs. Palin. The governor of Alaska for nearly two years, she is little-known outside of her state.

So far, Mrs. Palin has not conducted a formal news conference or taken questions from reporters, and no such sessions were scheduled today. Her only statement yesterday disclosed that her daughter Bristol was pregnant and that she would marry the baby’s father.

That news was followed by the announcement that a private lawyer had been hired to represent Mrs. Palin in a state investigation into her firing of the state’s public safety commissioner.

“We’re proud of Bristol’s decision to have her baby and even prouder to become grandparents,” the statement said.

The man who led McCain’s search for a vice-presidential nominee said he thought all the possible red flags unearthed during the background check had now been made public.

Under the weight of Gustav, speeches at the convention on Monday were light on red-meat rhetoric and heavy with appeals for donations to victims of the Gulf Coast storm, which was the main message in brief remarks from Laura Bush and her would-be successor, Cindy McCain.

“This is a time when we take off our Republican hats and put on our American hats,” said Mrs. McCain.

Added the first lady, “Our first priority for today and in the coming days is to ensure the safety and well-being of those living in the Gulf Coast region.”

Mr. Obama also appealed to his supporters, asking them in a mass e-mail and text message to donate to the Red Cross. His schedule for the rest of the week was also up in the air as he returned to Chicago headquarters to monitor the storm’s aftermath.

Outside the Xcel Energy Center where the convention officially began, police contended with thousands of protesters, some of whom attacked a group of Connecticut delegates.

Others smashed cars, punctured tires, and threw bottles, while many marched peacefully in a gathering that was initially conceived as an anti-war demonstration. Police arrested a few protesters for lighting a trash container on fire and pushing it into a police car.