CONCORD, N.H. — Politicians like to say campaigns are a marathon, not a sprint. But New Hampshire is turning into a relay-race, with presidential candidates and their spouses handing off the baton to each other over the next few days.

Jill Biden, wife of Vice President Joe Biden, kicked things off Friday, stopping by campaign offices in Concord, Berlin, Conway and Laconia. She’ll be followed in quick succession by President Barack Obama on Saturday, the vice president on Monday and first lady Michelle Obama on Tuesday.

Meanwhile, Republican Mitt Romney’s wife, Ann, will campaign in the state on Monday, and Romney himself plans to hold a rally Tuesday evening in the Manchester area.

Republican vice presidential nominee Paul Ryan made two trips to New Hampshire in late September, but Romney hasn’t been in the state since Sept. 6, the same day Obama, Biden and their wives campaigned in Portsmouth. Biden has been back twice since then; Obama returned for a rally last week.

The activity underscores the degree to which New Hampshire’s four electoral college votes are valued in what is expected to be a close election. And while the Obama campaign has logged more high-profile visits recently, the Romney campaign insists it has momentum on its side.

A WMUR-TV Granite State poll released Oct. 9 showed Obama with a slight lead over Romney in New Hampshire. A Suffolk University/7 News poll released a week later showed the two tied. Romney also recently began running television ads in the Boston market, which stretches into southern New Hampshire.

“The Obama campaign seems to be panicking,” Romney spokesman Ryan Williams said Friday. “That’s why you’re seeing steady stream of visits from the candidates and their spouses in next several days.”

In Concord on Friday, Jill Biden urged volunteers to sign up for a few more shifts and to make a few extra calls, saying their efforts could make the difference. Biden, who teaches English at a Virginia community college, emphasized the Obama administration’s efforts to make college more affordable, and highlighted what she called the “kind of scary” things Republicans have said about women’s health care and reproductive rights.

“So many women of my generation, we fought so hard for Roe vs. Wade, for access to contraception and for equal rights. We want to make sure our daughters and granddaughters don’t have to re-fight those battles we fought decades ago,” she said. “Everything we fought for is at stake.”

Biden also spent a few minutes making calls to supporters to thank them for their efforts. Sitting next to her was volunteer John King, who twice asked the undecided voters he was calling if they wanted to talk to the vice president’s wife. Both turned down the offer.

“They dissed her,” he joked, then clarified that both voters said, “No, thank you.”

King said he’s been surprised that the undecided voters he’s spoken to tend to be older. Most say the economy is driving their decision. Some days he’s had success nudging them toward Obama, he said, while other days are less successful.

“But it’s not over till it’s over,” he said.