ST. PAUL, Minn. -- Natural and human dramas off stage competed with fleeting appearances by Cindy McCain and First Lady Laura Bush in the Xcel Center yesterday as Republican delegates opened the convention that will nominate Arizona Sen. John McCain and Alaska Gov. Sarah Palin for president and vice president.

Instead of the partisan rhetoric that would normally have filled the opening session, speakers offered words of solidarity for victims of Hurricane Gustav. And, as if the storm was not enough of a distraction, the delegates made their way to a heavily guarded convention site surprised by Ms. Palin's announcement that her unwed 17-year-old daughter was pregnant.

Despite the surprise, there were no early indications that the news would reverse the widespread approval that social conservatives had given to the choice of Ms. Palin as Mr. McCain's running mate.

After an opening session that appeared more like a large stockholders meeting than a political gathering, the convention may be about to revert to typical partisan pageantry.

Convention organizers were still not able to offer a revised schedule, but McCain aides told reporters earlier in the day that they now hoped that their candidate would be able to accept his nomination in person Thursday night.

After a few hours of a bloodless, bare-bones agenda, the delegates finally got a chance to do some real cheering as Mrs. Bush walked onstage and noted that her husband, who was to have been the night's featured speaker, was on the Gulf Coast to oversee the hurricane response effort.

Politically, that might not have been bad thing for the Republicans. President Bush's historically low approval ratings are rooted in part in the criticism of his administration's reaction to Hurricane Katrina, almost exactly three years ago.

But Mrs. Bush echoed Mr. McCain's observation the previous day that this was not a time for politics.

"When such events occur, we are reminded that first, we are all Americans -- and that our shared American ideals will always transcend political parties and partisanship," she said.

Mrs. McCain joined her on stage to issue an appeal for the delegates and the wider audience watching on television to contribute to the hurricane relief efforts.

The Obama campaign had offered a similar plea to its supporters and to the millions of names on its e-mail list, urging donations to the American Red Cross.

The announcement of Bristol Palin's pregnancy was yet another unexpected turn in what is shaping up as the most unscripted convention in memory.

"We're proud of Bristol's decision to have her baby and even prouder to become grandparents," Ms. Palin said in a statement. "As Bristol faces the responsibilities of adulthood, she knows she has our unconditional love and support.

"Bristol and the young man she will marry are going to realize very quickly the difficulties of raising a child, which is why they will have the love and support of our entire family. We ask the media to respect our daughter and Levi's privacy as has always been the tradition of children of candidates."

The campaign later confirmed that the father is Levi Johnston, 17, a high school student in Wasilla, Alaska.

The announcement came after some left-wing blogs had circulated clearly unfounded rumors that the new baby born to the Alaska governor five months ago was actually her daughter's child.

Social conservatives were supportive. Tony Perkins, the leader of FRC Action, the political wing of the influential Family Research Council, issued a statement noting that "teenage pregnancy has become all too common in today's society regardless of a family's economic or social status.

"Fortunately, Bristol is following her mother and father's example of choosing life in the midst of a difficult situation. We are committed to praying for Bristol and her husband-to- be and the entire Palin family as they walk through a very private matter in the eyes of the public," he said.

Dr. James Dobson, one of the nation's most prominent evangelical Christians, and a traditional foe of Mr. McCain's, announced he would vote for the Republican ticket only after the selection of the ardently anti-abortion Alaska governor.

He, too, offered his support in a statement. "Being a Christian does not mean you're perfect. Nor does it mean your children are perfect," he said.

Mr. Obama echoed the view that the story should be insulated from the political debate.

"I have said before and I will repeat again: People's families are off limits," Mr. Obama told reporters after a campaign stop in Michigan. "And people's children are especially off-limits. This shouldn't be part of our politics. It has no relevance to Gov. Palin's performance as a governor or her potential performance as a vice president. So I would strongly urge people to back off these kinds of stories."

Mr. Obama was adamant that his campaign had not played a role in goading the Internet speculation about Ms. Palin.

"I am offended by that statement," he said. "Our people were not involved in any way in this, and they will not be. And if I thought there was somebody in my campaign who was involved in something like that, they would be fired."

Mr. Obama is curtailing his campaign schedule today until the effects of the hurricane become clear. His running mate, Sen. Joseph R. Biden Jr., dropped plans to march in Pittsburgh's Labor Day parade in deference to the storm yesterday although he did continue on to a sentimental journey to his old home in Scranton later in the day.

Mr. Obama was considering another swing through Pennsylvania later in the week, subject to storm developments, but his campaign had yet to release any details of that schedule last night.

Earlier yesterday, Republican delegates quickly approved a platform whose abortion plank does not provide exceptions allowing abortion in cases of rape, incest or where a mother's life would be in danger -- all favored by Mr. McCain. Ms. Palin, the Arizona senator's running mate, opposes abortion in all cases, consistent with the platform.

Plans for the balance of the GOP convention were similarly up in the air. As he gaveled yesterday's session to a close, Republican National Committee Chairman Mike Duncan's only guidance was: "The chair will notify delegates regarding reconvening of the convention."