Sen. Bernie Sanders (I-Vt.) has some pretty ambitious ideas about tackling rising health care costs, a warming climate and the stagnant minimum wage.

But the 77-year-old Vermont senator, who on Tuesday launched his second bid for the Democratic presidential nomination, isn’t yet on board with a push to eliminate what could be one the biggest obstacles to getting his proposals through Congress: the filibuster.

“No, I’m not crazy about getting rid of the filibuster,” Sanders said in an interview with CBS that aired on Tuesday when asked whether he supports getting rid of the chamber’s longstanding 60-vote threshold on legislation.

“The problem is, people often talk about the lack of comity, but the real issue is you have a system in Washington that is dominated by wealthy campaign contributors,” he added.

It’s difficult to see any of Sanders’ major policy proposals passing in the Senate without a change to the chamber’s longstanding 60-vote threshold on legislation even if Democrats win the White House and Senate in 2020.

Policy ideas Sanders wants to become law like Medicare for All, the Green New Deal and tuition-free college are all vehemently opposed by Republicans. Moreover, it’s not clear whether they would receive unanimous support among Democrats, either. Sen. Amy Klobuchar (D-Minn.), for example, doesn’t think proposals like Medicare for All and debt-free college are plausible in the near future.

“If I was a magic genie and could give that to everyone and we could afford it, I would,” Klobuchar, who is also running for the Democratic presidential nomination in 2020, told a student at a CNN town hall on Monday when asked whether she could support Sanders’ free college idea.

Sanders isn’t the only member of the Democratic Senate caucus who is reluctant about the idea of doing away with the filibuster. Many of his colleagues defended retaining the threshold in interviews with HuffPost earlier this month, raising concerns about a scenario in which Republicans once again controlled both Congress and the White House with no Democratic ability to block far-right policies.

“If last year we did not have the filibuster, the Trump administration and the GOP majority could have rammed through an incredible range of laws that those same progressive groups would find incredibly destructive,” Sen. Chris Coons (D-Del.) said.

Other Democratic presidential hopefuls also share concerns about going nuclear to kill the filibuster, including Sens. Cory Booker (D-N.J.) and Kristen Gillibrand (D-N.Y.). Sen. Elizabeth Warren (D-Mass.), meanwhile, was the only 2020 Democratic presidential hopeful who did not rule out the prospect of going nuclear in a Democratic-controlled Senate.

“Everything stays on the table. You keep it all on the table. Don’t take anything off the table,” she said last month.

Of course, a future Democratic president could simply declare a national emergency to get what they want without congressional approval. That’s a scenario that many Republicans are warning President Donald Trump about following his move last week to build a wall on the southern border even though Congress has repeatedly rejected his funding demands.