WASHINGTON — There are still eight months to go before the first votes of 2016 take place in the Iowa caucuses, enough time for a challenger to rise and pose a threat to Hillary Rodham Clinton’s place as the front-runner for the Democratic Party’s presidential nomination.

But today? After former Rhode Island Sen. Lincoln Chafee’s entry into the race, the Democratic field is largely set, and it’s hard to see the contest as anything other than Clinton … and the rest.

The former secretary of state, New York senator and first lady has a commanding lead in early-state polls, the support of a fundraising operation left over from President Barack Obama’s re-election in 2012 and longtime alliances inside the party that are hard to look past.

Take, for example, the American Federation of Teachers, which met with candidates this week as part of its process to decide on a 2016 endorsement. To get it, they’ll have to win over a group that endorsed Clinton’s presidential campaign in 2007 and is led by Randi Weingarten, a longtime Clinton ally.

If there is a surprise candidate with the political skills and organizational talent to emerge as Obama did in 2007, he or she remains hidden from view. The most likely to play that role, Massachusetts Sen. Elizabeth Warren, is sitting out this campaign.

Unlike the GOP field, which will grow to 10 major candidates on Thursday, with more still to come, those who seek to challenge Clinton for the nomination make for a tidier group.

There’ll be no problems fitting Chafee, Vermont Sen. Bernie Sanders and former Maryland Gov. Martin O’Malley onto a debate stage with Clinton. That will hold even if former Virginia Sen. Jim Webb decides to make his exploratory committee a full-fledged campaign.

Clinton allies argue that creates a primary contest that’s just what she and the party need: enough of a competition to keep her sharp, but not so much as to create trap-doors that could damage her in the general election.

“She will be a much better general-election candidate having flexed her debate muscles and her rapid-response muscles,” said Maria Cardona, a former Clinton campaign aide. “It will take away a Republican talking point that this is a coronation.”

All three men see themselves as more than pacesetters. Sanders and O’Malley, for example, have offered economic plans more sweeping in their scope than an approach that Clinton has described, calling for the break-up of Wall Street banks and advocating for raising the minimum wage to $15 an hour.

A snapshot of Clinton’s challengers and what’s driving them to take on what appears to be a political mission: impossible.

 

Lincoln Chafee

A former Republican turned independent who joined the Democratic Party two years ago, the former Rhode Island senator and governor cites Clinton’s 2002 vote for the invasion in Iraq as the driving force behind his candidacy. The next president, he says, should not be someone who backed the more than decade-long war.

While Chafee is more willing to critique Clinton than other Democrats, raising questions about her foreign policy positions and financial dealings, he has no significant campaign organization and isn’t raising money for a bid whose motives bewilder even longtime allies.

Among his campaign motivations, he said Wednesday, is ending capital punishment, taking an “open-minded approach” to drug trafficking and moving the U.S. to the metric system.

 

Martin O’Malley

The former Baltimore mayor left office as Maryland’s governor in January, after term limits kept him from seeking a third term in Annapolis. He passed on an unexpected chance to run for Senate, following Sen. Barbara Mikulski’s decision to retire, to seek the White House.

The 52-year-old O’Malley casts himself as the face of the party’s next generation, a not-so-subtle contrast to Bill and Hillary Clinton’s longtime roles in the party. He routinely points to his record on a raft of issues important to liberals, including gay marriage, gun control and environmental protection.

But he’s been reluctant to take Clinton head on. During an event Wednesday at the U.S. Hispanic Chamber of Commerce, he dodged the opportunity to directly compare himself to her, saying he was running because “the American dream that we share is in deep trouble.”

 

Bernie Sanders

The so-called democratic socialist has been talking about income inequality for years and has made it the centerpiece of his unlikely campaign.

An independent who has caucused with Senate Democrats, Sanders could offer Warren’s supporters a way to vote for a candidate who cares most of all about the growing chasm between the rich and poor, and Wall Street excess.

 

To be determined

Webb, a former Virginia senator and Navy secretary, would bring his background as a veteran and expertise in foreign policy to the field. He’s still trying to decide if he can raise the money needed to be viable.

Vice President Joe Biden has said he will announce his own decision later this summer, but he has taken few outward steps to prepare for a campaign. The recent death of his 46-year-old son, former Delaware Attorney General Beau Biden, further dampens the likelihood he will seek the presidency a third time.