Hillary Is In

And the most interesting Democratic presidential race in decades is on.

HILLARY RODHAM Clinton's announcement Saturday that she is entering the Democratic presidential race is not a surprise, but that doesn't take away from its significance. There has been a flurry of justifiable excitement over Sen. Barack Obama (D-Ill.), but Ms. Clinton's candidacy is equally momentous: Never before has there been a female presidential contender with such a strong prospect of winning the White House. As with Mr. Obama, that is a development to be welcomed by Americans of both parties.

Ms. Clinton enters the Democratic race as the immediate front-runner, with impressive experience in her husband's White House and on her own in the Senate and with an unmatched political operation. She is a disciplined campaigner with a broad grounding in domestic and foreign policy. She also has $14 million in the bank and the proven ability to harvest millions more.

But if Ms. Clinton begins with formidable assets, she also faces formidable challenges. One involves the Democratic base and its unhappiness with her position on the war in Iraq. Unlike Mr. Obama, who wasn't in the Senate at the time but made his opposition clear, Ms. Clinton voted to authorize the war; she has been more reluctant than some of her Democratic rivals, most notably the 2004 vice presidential nominee, John Edwards, to renounce that backing or to call for immediate departure of the troops. "I am cursed with the responsibility gene,'' Ms. Clinton told the New York Times in an interview upon returning from Iraq last week. "You've got to be very careful in how you proceed with any combat situation in which American lives are at stake.''

More than a little self-serving, perhaps, but Ms. Clinton's approach is, in fact, more responsible than those of some of her opponents. While this is good policy, it could be risky politics, especially in states that hold early primaries. The trick for Ms. Clinton will be to navigate the primary process on the war and other issues in a way that attracts, or at least assuages, liberal voters while not casting her as a poll-driven panderer or locking her into positions that could complicate a general election campaign.

A second and somewhat contradictory issue for primary voters is the matter of Ms. Clinton's "electability": Is she such a polarizing figure, with such high negatives (44 percent in the latest Washington Post-ABC News poll, compared with 29 percent for Mr. Obama) that she would be at a disadvantage in the fall campaign? The question about Hillary Clinton may be not so much whether a woman can win the presidency but whether this woman can.

The Clinton campaign confronts this problem directly on its Web site. Chief strategist Mark Penn argues that the candidate's poll ratings are strong, that she has demonstrated in New York the ability to win over voters in Republican areas and that she is "the one potential nominee who has been fully tested." That may be true, but for Hillary Clinton, the toughest test is still ahead.