Democratic Sen. Hillary Rodham Clinton is determined to show no weakness in a re-election race that's a possible precursor to a White House run. Her campaign is pummeling her little-known Republican rival.

The former first lady looks to be cruising toward a second term: She has $22 million while challenger John Spencer, the former Yonkers, N.Y., mayor, has the baggage of fathering two children with an aide while married to another woman.

Yet, in the two weeks since the state primary, the Clinton campaign has launched a surprisingly vigorous assault on Spencer, painting him as an ideological extremist and a hothead who once threatened to kill Republican Gov. George Pataki. Spencer said he was joking.

Almost no one thinks Clinton faces any real threat from Spencer, a conservative who opposes abortion rights and had just $800,000 in his campaign account at the end of August. A recent Siena College poll showed Clinton trouncing Spencer, 62-33 percent.

Still, analysts say this Senate contest will have implications if she moves, as some predict, toward a presidential bid.

Besides scoring a decisive win, Clinton must show strength in the state's more conservative upstate and rural areas. She also must rally her Democratic base, who may not be motivated to vote since she and Democratic gubernatorial candidate Eliot Spitzer are both expected to win handily.

To accomplish that, analysts say Clinton needs to be do more than just ignore — and then easily dispense with — a token candidate.

"They've made a decision to inflate Spencer so they could show the rest of the country that they could defeat a conservative menace," political strategist Bill Cunningham said. "If she has no real opponent, there's no real way to check out her electability nationwide."

So after virtually ignoring her Democratic primary opponent, anti-war activist Jonathan Tasini, the Clinton team has criticized Spencer as an intemperate bomb thrower unable to abide by his own pledge to run a positive campaign.

"GOP senate candidate John Spencer negatively attacked Senator Clinton five times in a radio interview yesterday. Spencer has previously threatened to kill Governor Pataki, a federal judge, and several Yonkers city commissioners and their families," wrote Clinton spokesman Howard Wolfson in one of many e-mails since Spencer won his party's primary Sept 12.

Spencer has acknowledged making threatening comments against Pataki and other officials during his tenure in Yonkers, but insisted it was in jest.

Without enough money to buy television ad time, Spencer has tried to raise his profile through interviews on cable television and talk radio. The Clinton campaign routinely sends out e-mails after these appearances denouncing Spencer for anything he says about Clinton and her record.

Wolfson has also reminded reporters that Spencer once publicly referred to Italians as "goombahs," and that he ran a television ad over the summer pairing photos of Clinton and Osama bin Laden.

On Sunday, Wolfson followed up a Spencer radio appearance, noting the Republican had told an interviewer last spring that Clinton was part of "an attack on religion and God."

"In Mr. Spencer's world, accusing his opponent of attacking religion and God is so routine that it's forgettable, comparing a United States senator to Osama bin Laden isn't negative, and threatening to murder public officials is just a big joke," Wolfson wrote.

In an interview, Wolfson said Clinton "takes every campaign seriously" and that Spencer's remarks could not go unanswered.

"Mr. Spencer has been ranting and raving. He's attacked Sen. Clinton every day," Wolfson said. "He is the Republican candidate for Senate, and we intend to hold him accountable."

Spencer's pollster, John McLaughlin, said voters would recognize the strategy as an effort to bolster her stand for 2008.

"They're looking at this as the first round of the presidential race," McLaughlin said.