Last night Hillary Clinton became the official underdog in the Democratic race. Results from the three-state Potomac Primary showed Barack Obama, armed with momentum coming out of last weekend’s contests, driving Senator Clinton, clearly waning in support, into second place in the elected delegate count.

Even Virginia, in which she held out a slim hope of victory, gave Senator Obama a resounding win. Strangely, achieving back marker status may be the best news to have emerged for Mrs. Clinton last night, for in the Democratic Party, to be the underdog is to attract a substantial sympathy vote.

With Senator McCain the all but certain Republican candidate — it would take rather more than a miracle for Governor Huckabee to win the nomination, whatever happened in Virginia last night — the shape of the November election is coming into view. While conservatives must ponder whether Mr. McCain is close enough to their views to warrant their support, Democrats must ask who is the most likely to defeat the Arizona senator.

If Mrs. Clinton is to emerge as her party’s contender, she has three weeks to make the case that it is she, not her rival from Illinois, who is best able to defeat Mr. McCain. Mrs. Clinton believes she can convincingly win on March 4 in Texas, a state that offers 193 delegates, the largest cache of delegates in the country, as well as most of the 161 delegates in Ohio on the same day. If on April 22 she also can capture by a wide margin a majority of the 158 delegates in Pennsylvania, in a closed primary that does not allow independents to join in, she may have enough votes to claim victory.

In the next 21 days, however, Mrs. Clinton hopes that her party’s love affair with Mr. Obama turns sour. She has been making the case, largely in vain, that she is best prepared to be effective in the White House. Although Mr. Obama has no executive experience of any sort, Democrats do not seem to care.

She also has been pressing her detailed program, particularly her economic policies, which, as the country teeters on the edge of recession, are designed to put middle class voters’ minds at rest. Here there is some room for her to be optimistic. Mr. Obama’s strength is in his appeal to those largely outside the economic mainstream: the young, African-Americans — nine to one broke in his favor in Virginia last night — those who earn more than $100,000, and those who have more than one university degree.

In Texas and Ohio, Mrs. Clinton is hoping blue collar workers who have always supported her, joined in Texas by Hispanics who have always been loyal to her and her husband, will turn the race back in her favor. If she were to win in three weeks’ time, what Senator Clinton will be able to argue is that in the huge states which are demographically more like the country at large, such as New York, California, and Florida, she proved to be a winner. And that Mr. Obama’s failure to win in these states bodes badly for his prospects in November.

A third theme which Mrs. Clinton has been pushing, and which has so far failed to produce results, is that Mr. Obama remains a largely untried, untested, unknown, and underreported figure. She is correct. If she fails to win on April 4, the Democrats will have chosen a handsome, romantic, eloquent candidate about whom they — and we — know little. That ignorance will not last. If Mrs. Clinton’s allies in the press do not soon discover something embarrassing in Mr. Obama’s past, they will leave the job to the Swiftboaters and other Republican surrogates come November.

Mrs. Clinton’s appeal for more transparency about Mr. Obama’s back story is not a smear. He has admitted in his first memoir that in his youth he lived in a fog of marijuana and cocaine — an element of his life he did think fit to repeat in his second biography. It will not take the investigative talents of Messrs. Woodward and Bernstein to discover with whom Mr. Obama spent those many intoxicated hours and what they did during their stupor. For the senator to become the Democratic candidate before such questions are answered is, at least, inviting a hostage to fortune.

Questions linger, too, about Mr. Obama’s choice of church in Chicago. Like many, he shopped around to find a church that suited him. He finally chose the Trinity United Church of Christ, presided over by Reverend Jeremiah A. Wright, whose sermon, “The Audacity of Hope,” inspired the title of Mr. Obama’s second volume of memoirs.

Rolling Stone magazine, one of the few organs to have thoroughly explored the roots of Senator Obama’s thinking, described the senator’s attachment to the church and the teachings of Reverend Wright as “as openly radical a background as any significant American political figure has ever emerged from, as much Malcolm X as Martin Luther King Jr.” The magazine quoted Reverend Jim Wallis, “a leader of the religious left,” saying, “If you want to understand where Barack gets his feeling and rhetoric from, just look at Jeremiah Wright.” Above all, there is the question of race. The discussion among Democrats about the effect of Mr. Obama’s race in the November election was brought to an abrupt halt either by President Clinton’s blundering, ill considered remarks or by liberal oversensitivity on color which forbids any mention of the subject, or perhaps a mixture of the two. Either way, the Democrats’ reluctance to address Mr. Obama’s race, and what its impact may be in a tight contest with Senator McCain, has left an inviting opportunity for those who would wish Mr. Obama defeated at any cost.

nwapshott@nysun.com