A majority of the Senate Democratic caucus is backing a bill that would raise the federal minimum wage to $15 just two years after a comparable bill introduced by Sen. Bernie Sanders (I-Vt.) received scant support from his colleagues.

Thirty of Sanders’ colleagues in the caucus joined the former presidential candidate in formally introducing the bill on Thursday, including Senate Minority Leader Chuck Schumer (D-N.Y.) and Sen. Patty Murray (D-Wash.), ranking member on the Health, Education, Labor and Pensions Committee. By contrast, just five senators co-sponsored Sanders’ 2015 bill raising the minimum wage to $15.

Schumer and Murray announced their support for the bill at an April press conference. At the time, however, the bill enjoyed the support of 23 other senators ― just shy of a majority of the Democratic caucus.

“The time is long overdue for us to raise the minimum wage, which is now, at the federal level, $7.25 an hour, which I think under any definition is a starvation wage,” Sanders said at a Thursday press conference on the bill’s introduction.

“We have got to raise the minimum wage to a living wage,” he said. “And what we are here to say is that living wage is $15 an hour.”

Mark Wilson/Getty Images Senate Minority Leader Chuck Schumer (D-N.Y.) is "feeling the bern" when it comes to the $15 minimum wage.

Sanders was flanked by Senate and House co-sponsors, including House Minority Leader Nancy Pelosi (D-Calif.), as well as low-wage federal contract workers from Good Jobs Nation, an offshoot of the labor union-backed “Fight for $15” campaign. Reps. Keith Ellison (D-Minn.) and Bobby Scott (D-Va.), the ranking member on the House Education and Workforce Committee, are introducing an identical companion bill in the House. The bill currently has 153 co-sponsors, a large majority of the House Democratic caucus.

Sanders was able to attract the support of party leaders and other more moderate colleagues by extending the phase-in period from 2020 to 2024, assuaging fears that a rapid increase would result in job losses. The largest hike in pay would occur right away if enacted, with the law lifting the federal minimum wage from $7.25 to $9.25 this July.

The federal minimum wage has not gone up since 2009, when former President George W. Bush approved the last of several gradual increases.

But after the Service Employees International Union launched the “Fight for $15” movement in 2012, a growing number of cities and states have adopted the $15 minimum, making it a major benchmark for progressive activists. Los Angeles, San Francisco, Seattle and the state of New York are all in the process of raising their minimum wages to $15.

Of course, with Republicans controlling the White House and both chambers of Congress, there is virtually no chance that this legislation will be considered, let alone pass. Democrats are instead using the bill to show the public what they would do if they had power, with a particular eye on their restless progressive base, which would like to see the party embrace Sanders-style economic populism.