As the Democratic Party lurches leftward, its ascendant liberal wing has sought out a champion. As is often the case, the party in control of the White House for two consecutive terms has soured on their party’s leader.

Conservatives will no doubt find it ironic that the most liberal president to occupy the Oval Office in a generation, a figure likely to hold that title for another generation or more if America’s penchant for pendulum swings continues apace, has been judged insufficiently committed to the left’s policy prescriptions. For months, the Democratic Party’s liberal wing has searched for an antidote to Barack Obama’s pragmatism; a trait that many believe will only be more pronounced in Hillary Clinton.

Progressive icon Sen. Elizabeth Warren (D-MA) has demonstrated that she is as much a careerist as any politician. She will not sacrifice her future by throwing her prospects on the pyre of liberal lost causes by committing to a quixotic White House bid. Sen. Bernie Sanders (I-VT), a self-described socialist, has about as much chance of winning the White House as Venezuelan dictator Nicolas Maduro – thought they both might draw approximately the same level of support from Iowa’s Democratic caucus-goers.

Sensing an opportunity, another liberal icon jumped in to fill the gap. In April, New York City Mayor Bill de Blasio presented himself as the arbiter of and champion for modern progressive values. The mayor briefly teased the press with the prospect of mounting a presidential run against Clinton, a woman he served as her U.S. Senate campaign manager in 2000, just months into his tenure in Gracie Mansion.

After he begged off the hollow ruse, de Blasio revealed his intention to craft a modern liberal manifesto that would force the Democratic Party’s nominee well to the left of the country. On Friday, elements of that document were revealed to the press. The document that was crafted with the support of liberals in Congress and enjoys the support of far-left ideologues like former White House advisor Van Jones, The Nation editor Katrina Vanden Heuvel, and actress Susan Sarandon is a veritable progressive wish list.

The future of liberalism according to de Blasio and his far-left allies is exactly what you would expect; no free trade, a comprehensive immigration reform plan with a pathway to citizenship for illegal residents, free child care and afterschool programs, national paid sick leave, and a $15 per hour minimum wage.

Any political observer who is not steeped in progressive mythology can see the trap that liberals are setting for the Democratic Party.

“After 16 months as mayor of New York, Bill de Blasio seems determined to escape the confines of his day job and to prompt a national liberal movement — even as he leaves himself open to criticism that he is not making problems at home a priority,” The New York Times reported on Tuesday.

In Washington this week, the mayor is scheduled to attend an event with Ms. Warren, before joining allies to unveil a list of federal policy demands, which he describes as the liberal equivalent of Newt Gingrich’s “Contract With America.” In California, the mayor is speaking at his daughter’s university and appearing with Robert Reich, the former labor secretary.

On Thursday in San Francisco, Mr. de Blasio is also set to attend a fund-raiser for the Campaign for One New York, a political nonprofit group established to advance his agenda. The group, which can accept large contributions outside New York City’s campaign finance limits, is paying for the mayor’s California trip.

The New York City mayor might be a major draw for Beltway-based progressive Democrats, but he’s no shining star back home. An NBC 4/Wall Street Journal/Marist poll released last week pegged de Blasio’s job approval rating at a dismal 44 percent, even in liberal New York City.

The Democratic Party would be best served if its ideological anchor were, you know, popular. Today, de Blasio is sowing the seeds of conflict in what should otherwise be an uneventful Democratic presidential primary. Either Clinton will be compelled to adopt positions out of step with the general electorate, or she will ignore her left flank and leave behind her a jilted progressive wing that will still be nursing their wounds in November of 2016.

De Blasio’s trap has been set, and only the most ideologically blinkered liberals cannot see it. Unfortunately for the Democratic Party, it is presently made up of more than a handful of ideologically blinkered liberals.