Democrats debate: Move to the center, or move left?

But there is a growing frustration among progressives who are now saying the party must move toward a more populist position on the issue that many on the left see as the great unfinished business of the Obama years: economic fairness.

“Look at where we are going to be at the end of the Obama administration — we’ll see a lot of change on social issues, but on the ground in the country we’ll still have this growing economic inequality,” said Neera Tanden, president of the liberal Center for American Progress.

Dating to his first appointments as president-elect, Mr. Obama has drawn suspicion from some elements of the left on economics. Now, with the first talk of the post-Obama Democratic Party, liberal angst is starting to take form in Washington.

Senator Elizabeth Warren, the former Harvard law professor who is suddenly Massachusetts’s senior senator as a freshman, has been at the center of two issues that will be sharply debated within the Democratic Party heading into 2016. Ms. Warren is drawing attention to the college students and recent graduates besieged by debt by proposing to offer them the same interest rate for a year, 0.75 percent, as the Federal Reserve offers banks.