After 10 years of turmoil in our national life that has challenged our confidence in our leaders, Americans are clearly in the mood to elect a candidate they trust to shake things up in Washington. No candidate embodies that mood more than Barack Obama.

We have had a president impeached and another selected by a dubious court decision despite winning a minority of votes. Terrorists attacked our nation on Sept. 11, 2001 and two wars have been fought in response. Though we were united in retaliating against al-Qaida in Afghanistan, the revelation that there were no weapons of mass destruction in Iraq has left our leaders struggling to explain a rationale for our commitment of military forces in that nation. The lackluster response to Hurricane Katrina despite years of preparation and millions of dollars spent on a new Department of Homeland Security crushed our confidence in the government's readiness to handle a crisis.

Barack Obama's life story, innovative campaign, soaring oratory and assumption-shattering appeal make him the best candidate to appeal to the national hunger for change.

The Obama story is the type of come-from-behind narrative that Americans love. In the last few change elections we ate up Jimmy Carter's peanut-farming background, Ronald Reagan's humble Illinois lifeguard roots and Bill Clinton's birth in a place called Hope to a struggling mother widowed before his birth.

In fact, despite Bill Clinton's avid opposition to the senator from Illinois, Mr. Obama is his most natural political heir. Mr. Obama, too, had a complicated family history. He was raised by an often-single mother and her parents, and admitted to prominent schools, without the benefit of family connections, where he excelled. Unlike so many of his classmates, Mr. Obama gave up the chance to earn wealth and prestige in New York or Washington to teach law, organize community initiatives and run for state office.

Despite the recent criticism of his word choices, candidate Obama is combining his optimistic message of "hope" and "change" with language that identifies with working-class anxiety, evoking memories of Bill Clinton feeling the nation's pain 16 years ago. Like a genial family doctor, Mr. Obama acknowledges Americans are hurting and coolly diagnoses the problem as the broken system in Washington, which does not care enough about them. He passionately explains why he is the one who can salve the wounds.

There are practical political reasons for Democrats to pit Mr. Obama against John McCain in the general election, too. Mr. Obama appeals more to voters across the spectrum, although the continuing fight with Hillary Clinton is not helping. In every state contest this winter and spring, Mr. Obama has won more independents than Mrs. Clinton or Mr. McCain. Combine that with the surge in Democratic registration and the large turnout in red, blue and purple states across the country, and the electoral college map could look very different this year from others in recent history.

According to Rock the Vote, youth voting is up 109 percent over 2004, with more than 3.9 million young people of ages 18 to 29 voting for Democrats while only some 1.7 million have voted for a Republican. African-American turnout is surging, too. Mr. Obama is the candidate of choice for most voters in both categories, while he continues to hold roughly 40 percent of white workers and Latinos, Mrs. Clinton's base voters.

Although he may not win them, Mr. Obama will make states like Mississippi, Louisiana and Georgia more competitive this year, forcing the cash-strapped Republicans to spend money down South to protect them. Meanwhile, he has a real shot at taking states like Virginia, Colorado and Missouri out of the GOP column. With Mrs. Clinton, Democrats are playing on the same old map, pinning all of our hopes on winning a few thousand more votes in Ohio and Florida than Mr. McCain.

Finally, because of the nature of the Democratic race and Mrs. Clinton's domination of the party establishment, Mr. Obama's campaing has been forced to be more creative and entrepreneurial. It has maximized the new technologies of Internet organizing and text messaging, marrying them with more traditional field campaigning. With the establishment's full embrace after winning the nomination, Mr. Obama's new organizing techniques combined with the efforts of labor unions and Democratic machines in places like Pennsylvania and Michigan likely would take the White House out of Republican hands.

The tough thing for Democrats is that John McCain says he wants to stand up against the Washington power structure, too. He touts campaign finance reform, environmental sensitivity and a contrarian attitude. But Democrats have plenty of evidence to make the case that Mr. McCain is really a Bush Republican in maverick's clothing who supports Mr. Bush's debilitating tax cuts and who would keep American troops stationed in Iraq for many more years, regardless of Iraqi officials' inability to come up with a political solution to the conflict in their country.

Mr. Obama's lead in popular votes, delegates and states won in the Democratic primaries and caucuses, and the choice of Mr. McCain by the Republicans, provides overwhelming evidence that Americans are ready for a change. This is a year to revive a mantra of the Bill Clinton presidential campaign in 1992, which was "change vs. more of the same."

If Hillary Clinton were to win the Democratic nomination, she would be the fourth member of the Bush and Clinton families vying to sit in the White House over the past 20 years. In today's political environment, choosing the former first lady to represent the Democrats could throw away our rhetorical advantage and strengthen Mr. McCain's case that he is the agent of change while Mrs. Clinton is just "more of the same."

Democrats love the Clintons, but this year our party must embrace Mr. Obama. He represents the change in course that Americans desperately seek.