Senator Kirsten E. Gillibrand, second from left, leaving a news conference in Huntington, N.Y., on Sunday.

As United States Senator Kirsten E. Gillibrand’s allies have elbowed out her would-be Democratic challengers one by one, they emphasized what was perhaps her most formidable weapon: her fund-raising muscle.

This month, Ms. Gillibrand will report that she has raised $7.1 million since her appointment last January, according to her advisers, making her one of the most prolific fund-raisers among Democratic senators during the off-election year despite the fact that she has never run statewide and has been in her post for roughly a year.

Eric Schultz, director of communications at the Democratic Senatorial Campaign Committee, described Ms. Gillibrand on Sunday as “a fund-raising star.”

But it is not clear that the senator’s knack for amassing cash will be enough to scare off Harold E. Ford Jr., the former Tennessee congressman who said last week that he was considering a primary campaign against her this fall.

Mr. Ford is quickly gaining attention and showing moxie where other challengers had not, saying he would run regardless of whether “party bosses” like the state’s senior senator, Charles E. Schumer, want him to.

Ms. Gillibrand and her staff were clearly caught off guard by the emergence of Mr. Ford, who moved to New York three years ago for a job in the banking industry after his failed 2006 run for the Senate from Tennessee.

After initially dismissing him, Ms. Gillibrand’s advisers are growing concerned that he could pose a real threat. Ms. Gillibrand interrupted a family vacation in Europe late last week to telephone the Manhattan Democratic Party chairman, Assemblyman Keith L. T. Wright, who has yet to endorse a candidate. She asked for his help in setting up a meeting with local party officials whose support she is courting.

On Friday, Ms. Gillibrand’s advisers held a series of conference calls, scrambling to devise a strategy to deal with Mr. Ford. The consensus that emerged was that the former congressman is a blank slate, and Gillibrand supporters needed to move quickly to highlight parts of Mr. Ford’s record that might prove troublesome for him, like his position on abortion rights. (While he described himself during the 2006 Senate race as “pro-life,” a Ford adviser maintained that it was an attempt to take back a term that he felt anti-abortion groups had unfairly appropriated. Mr. Ford, the adviser said, has always supported abortion rights.)

“They are going into overdrive,” said a person with direct knowledge of the deliberations who spoke on the condition of anonymity because the talks were supposed to remain private. The person added, “There is an intense focus on this threat.”

On Sunday, at an unrelated event in Huntington, N.Y., on Long Island, Ms. Gillibrand addressed the potential candidacy of Mr. Ford for the first time, saying, “Every candidate makes their own decision whether to run or not.”

Asked about Mr. Ford’s claims that her allies were trying to bully him out of the race, she suggested there was nothing untoward about her supporters’ making their preference known.

“Every politician in our state will make their own judgments about who they think is best for New York,” Ms. Gillibrand said. “So each person who has articulated a view on this issue, they have every right to do that, and that’s what politicians do. They advise and they inform people about what they think are the best choices for the state and for the government.”

Mr. Ford has said he will decide next month whether to enter the race. Among his considerations will be Ms. Gillibrand’s fund-raising performance, which she will officially report Jan. 31.

More . . .

"