When Senator Clinton strides onto the Dartmouth Green tonight for a Democratic presidential debate, she will do so with a bullseye on her back.

Until very recently, Senator Obama’s cache of support among liberal activists made him the focus of criticisms at presidential debates. Think of the three-way pounding Mr. Obama took at the AFL-CIO forum at Chicago’s Soldier Field for suggesting that America take military action in Pakistan without the approval of that country’s president. Tonight will be different. Liberals will likely turn their sights on Mrs. Clinton.

Some four months ahead of the first presidential primary, Mrs. Clinton stands on top in the polls in New Hampshire. A recent Franklin Pierce College/ WBZ survey had her leading Mr. Obama, 36% to 18%; a Rasmusen poll found her lead to be even greater, 40% to17%. Washington Post reporter Dan Balz captured the prevailing sentiment in a blog entry yesterday: “She now sits atop the Democratic field, in a tier by herself.”

While the debate will be broadcast nationally on MSNBC, it will air locally on New Hampshire Public Radio and New England Cable News, a regional 24-hour news network reaching 360,000 of New Hampshire’s households. The heavily watched Boston Red Sox will play early, at 5 p.m., permitting those who want to see the debate, to do so.

NECN’s veteran political reporter, Alison King, will be one of the questioners at the debate moderated by NBC’s Tim Russert. She sees presidential candidates close-up as much as any journalist in America. She says the focus will be on Senator Clinton. “I’m going to be looking to see how negative the other candidates are willing to get, how much dirt the other candidates are willing to throw out, and how nasty they’re willing to get,” Ms. King said. “The status quo isn’t working. Being nice isn’t working any more.”

She speculated on what grounds candidates might challenge her. “Are they going to going to get into her health care plan? Are they going to get into Whitewater?”

In recent weeks, the anti-Clinton tone within the race for the White House has sharpened. An advisor to Senator Edwards, Joe Trippi, called a Washington fundraising event for her campaign, “a poster child for what is wrong with Washington.” He added: “The truth is there aren’t many Americans who believe it is okay to take money from lobbyists and then sit them down with the chairs of the very committees that they seek to influence.”

An advisor to Mr. Edwards in New England, Michael Goldman, who consults at the Government Insight Group and has worked with presidential candidates such as Michael Dukakis and Bill Bradley, told The New York Sun: “If you take away the two coasts, she has tremendous problems getting elected.”

Reacting to a report that suggested President Bush hoped Senator Clinton becomes the Democratic Party’s nominee, Senator Dodd’s campaign sent out a terse statement. “I can understand why the President would want Senator Clinton to be the nominee,” it said.

While we can expect similar comments tonight, they are by no means guaranteed to work. Mrs. Clinton is not like Ronald Reagan, who was described as Teflon. Rather, because she has been subject to strong criticism for so long, it is almost as if much of the voting public already discounts it. Verbal battles with critics are now viewed as part of her psychic make-up.

“She would prefer this to eating breakfast, to going to the movies, to getting her hair done. She loves it. She revels in that forum,” a one-time Democratic candidate for governor in New Hampshire and a morning talk show host on WCCM-AM, Arnie Arnesen, says. “She is authentically happy up there. Most human beings get nervous walking into that. That is so scary.”

A bevy of blows directed at Mrs. Clinton tonight may have the unanticipated effect of helping her campaign. She already benefits by being one woman in a sea of men. There are voters in New Hampshire, particularly senior citizens, who find the sight of men aggressively criticizing a female candidate unseemly. Her opponent in the 2000 Senate race, Rick Lazio, learned that the hard way.

Senator Clinton’s ability to withstand withering attacks could remove one of the strongest arguments against her candidacy — that she has too much baggage to weather Republican attack. Dartmouth College could well serve as her proving ground.