WASHINGTON — Eight days before the election, President Barack Obama switched from campaigner to hands-on commander of the federal response to Hurricane Sandy as the sprawling storm roared menacingly toward the Eastern Seaboard.

Republican Mitt Romney scaled back his appearances and urged supporters to “do your very best” in donating to relief efforts.

The political pace quickened Monday even without the customary clash of rallies and rhetoric. Romney’s allies put down $1.2 million for a last-minute TV ad campaign designed to make Pennsylvania competitive — or at least appear so — and the roll of early voters swelled past 15 million in scattered states.

With the race in its final full week, most national polls showed the two presidential rivals separated by a statistically insignificant point or two, although others said Romney had a narrow lead for the overall popular vote.

But the election will be won or lost in the nine most competitive states. Republicans claimed momentum there, but the president’s high command projected confidence. And Romney’s increasingly narrow focus on Iowa, Wisconsin and Ohio suggested he’s still searching for a breakthrough in the Midwest to deny Obama the 270 electoral votes needed for victory.

The president changed roles quickly during the day, highlighting the advantages of the incumbency — as long as events go smoothly. He scrapped a morning campaign appearance in Florida, boarded Air Force One for a bumpy flight to the nation’s capital and appeared before reporters in the White House not long afterward.

“We’re making sure that food and water and emergency generation is available for those communities that are going to be hardest hit,” he said.

At the same time, Obama soberly warned that heeding evacuation orders from local authorities was paramount for those in the storm’s path.

“Do not delay. Don’t pause. Don’t question the instructions that are being given, because this is a serious storm and it could potentially have fatal consequence if people haven’t acted quickly,” he said.

The president didn’t mention the campaign in his prepared remarks, and when he was asked how the storm might affect the election, he said he wasn’t thinking along those lines.

“I’m worried about the impact on families, and I’m worried about the impact on our first responders. I’m worried about the impact on our economy and on transportation,” he said.

Romney went ahead with part of his campaign schedule, although he blended his appeal for political support with one for his backers to make a donation to the Red Cross or other relief agencies “in any way you can imagine to help those in harm’s way.”

“Do your very best to help,” he implored as his aides spread the word he would cancel an evening appearance in Wisconsin and a full day of campaigning today because of the storm.

Aides said the Republican might visit with storm victims later in the week, as he did when Hurricane Isaac raked the Gulf Coast the week of the Republican National Convention.