Bernie Sanders ran for president promising a political revolution. When he did not secure the Democratic nomination, the unapologetic progressive immediately threw in as a supporter of a more moderate Democrat, Joe Biden, and became an ardent advocate for his former rival.

But that does not mean that Sanders has lost his revolutionary zeal.

In recent days, the independent senator from Vermont has become the highest-profile and most enthusiastic congressional champion of the argument that Senate Democrats must use their narrow majority to enact a transformational agenda. Sanders has made it clear that he is pleased by the ambitions of the White House when it comes to strategies like those outlined in the president’s initial proposal for an American Jobs Plan. But he has been equally clear in recent days about his frustration with the deference many Democrats continue to show to Republicans who are delaying and disrupting the governing process.

The Biden administration has been engaged in a delicate dance of negotiations with a small group of Republican senators, maintaining the faint hopes of reaching an agreement to approve the president’s infrastructure proposal. Republicans, some Democrats, and many pundits who are unable to get over the delusion of “bipartisanship,” have suggested that compromise is necessary to enact a more modest proposal.

But Sanders isn’t having it.

“If Republicans don’t want to cooperate and help us seriously address the many crises we’re facing today,” he says, “then, yes, we have to move forward without them to rebuild our crumbling infrastructure and create millions of good-paying, union jobs.”

This is about much more than the usual wrangling between Democrats and Republicans. Sanders has a longer and more ambitious history of working with Republicans who really want to get things done—on issues ranging from fair trade to protecting civil liberties and auditing the Pentagon—than the vast majority of congressional Democrats. But the senator is unwilling to play the fool. If Republicans fail to bargain in good faith, he is prepared to abandon negotiations and start governing.

That’s an emerging view on the part of progressives, who argue that the handful of Senate Republicans who are talking with Biden—and who have proposed weak-willed alternatives to the president’s agenda—are not taking the discussion about the American Jobs Plan seriously. Activists with the Sunrise Movement gathered outside the White House Friday to call for approval of “the boldest version of the American Jobs Plan.” “No Compromise, No Excuses,” declares the group. “Democrats must take their power seriously and stop negotiating with a GOP who is not serious about climate action or delivering for the American people.”

Sanders is delivering a similar message with interviews, statements, and social media messages that suggest the time to act has arrived.

When CNN’s Wolf Blitzer floated a case for continued negotiations and compromises on the part of Democrats, the senator shot it down.

“The Republicans say they’re on board with a lot of President Biden’s plan when it comes to ‘traditional’ infrastructure—roads, bridges, airports, stuff like that,” argued Blitzer. “Are you and other progressives denying President Biden potentially a bipartisan ‘win’ by including all of the other issues that you’re labeling infrastructure that Republicans say is not really traditional infrastructure?”

The Senate Budget Committee chair answered with facts, rather than wishful thinking.

“According to the experts in our country, the American Society of Civil Engineers, what the Republicans are proposing for ‘traditional’ infrastructure is only a fraction of what we need,” said Sanders. “I think every American understands that our roads, and our bridges, our water systems, all of that, is really crumbing before our eyes. I’m a former mayor, and what I know is that, unless you invest in infrastructure, it’s only going to get worse—and it’s only going to be more expensive. We now have the opportunity to create millions of good-paying, often union jobs rebuilding our infrastructure. What the Republicans are talking about is totally inadequate.”

Totally inadequate. And totally antidemocratic.

As Sanders and his fellow progressives note, Democrats won the presidency, control of the House of Representatives, and control of the Senate in the 2020 election cycle. Now, under any reasonable measure of how the system is supposed to work, the Democrats ought to be governing. And if filibuster reform is required to jump-start the process, so be it.

Echoing the urgency of more than 100 groups that on Thursday declared, “We cannot allow the filibuster to stand in the way of progress or imperil the health of our democracy,” Sanders says, “The U.S. Senate is the only institution in the world where a vote of 59-41 can be considered a defeat instead of a huge victory. Enough is enough. Let us change the outdated rules of the Senate, end the filibuster and pass a bold agenda for working families with a majority vote.”