Sen. Ed Markey Credit: Victoria Pickering

Last month, Senator Ed Markey said in a statement that “[a] smaller infrastructure package means fewer jobs, less justice, less climate action, and less investment in America’s future,” and so we should “not waste time trading the necessary scope and scale of this critical infrastructure package for Congressional Republican votes that have yet to and will never materialize.”

On Thursday, the Massachusetts Democrat said on MSNBC that any infrastructure bill which “does not have aggressive solutions to the climate crisis will just have that response which I`ve been giving which is: no climate, no deal.”

Markey’s red line has not shifted, but his political analysis has. In May, Markey was sure Republicans would never vote for a compromise bill. In June, he is worried they might.

Markey is not alone. The Washington Post recently reported that Senator Ron Wyden of Oregon, the chair of the powerful Senate Finance Committee, “would reject a deal that did not address the climate crisis or raise taxes on multinational corporations.” Senators Martin Heinrich (D-N.M.), Jeff Merkley (D-Ore.), Michael Bennet (D-Colo), Sheldon Whitehouse (D-R.I.), and Brian Schatz (D-Hawaii) made comments on Twitter this week suggesting they could also withhold their votes if the bill lacked sufficient climate provisions, but stopping just short of making a flat ultimatum.

This pushback from the climate hawk left comes as five Republican and five Democratic senators announced a rough outline for a potential deal, one that may go light on reducing greenhouse gas emissions. One of the Republicans involved, Senator Mitt Romney, triggered progressive concerns when he said of the nascent agreement. “The Democrats’ climate agenda is probably something they pursue by and large outside of an infrastructure bill,” the Utah Republican said. Sen. Jon Tester, the Montana Democrat, who also is in the room, tried to manage expectations of his caucus, telling the Post, “There are some people that are going to say the climate provisions are more than enough, there are other people that are going to say it’s not adequate.”

Up until now, when we have analyzed our evenly divided Senate, Sen. Joe Manchin has received the majority of the attention. As the West Virginian is one of the few Democrats who represent a state won handily by Donald Trump, holds bipartisanship as an important value and mockingly dismisses progressive pressure tactics, he is able—and potentially willing—to prevent his party from passing major agenda items on party-line votes. He is joined by Sen. Kyrsten Sinema as the only Democrats who have been unequivocal in their support for keeping the filibuster, along with touting the importance of bipartisanship. And in a 50-50 Senate, either one of them on their own can prevent the Majority Leader from circumventing the filibuster and passing legislation on a party-line vote through the budget reconciliation process. That gives them power beyond their individual vote.

Do the climate hawks possess the same power as the bipartisans? It depends.

If a bipartisan infrastructure deal attracts 10 Republicans, any progressive Senator can break ranks and side with the remaining Republicans in a filibuster to kill it. But if a bipartisan deal manages to attract more than 10 Republicans, the number of Democrats needed to mount a filibuster increases as well.

If a deal attracts fewer than 10 Republicans, that could prompt the bill’s proponents to pursue reconciliation. Manchin and Sinema could accept reconciliation for a bipartisan bill but not a partisan bill. Then the threshold for passage decreases to 50, while the number of defectors needed to kill the bill increases to some number above one.

Another factor is party pressure, and presidential pressure. If Biden is reluctant to accept a bipartisan deal, he could tell Majority Leader Chuck Schumer to proceed with a partisan budget reconciliation process. But Manchin and Sinema could refuse to go along. Manchin in particular—as a senator from a deep red state—may well be completely immune to pressure from the leaders of his party, even though he did participate in a Democratic-only approval of the president’s Covid relief bill.

If Biden accepts a bipartisan deal, some climate hawks may find it hard to resist signing on. Past polls have indicated that a sizable majority of Democratic voters—in stark contrast with Republican voters—want their elected officials to “make compromises with people they disagree with.” So in a scenario where a president with strong job approval ratings—especially among Democrats— is pressuring Democratic senators to support a compromise, the senators’ Democratic constituents, despite their shared concerns about the climate, may back up Biden.

To strengthen their leverage, climate hawks will need a red line position that resonates with their constituents and dampens that hunger for compromise. So far, these senators are speaking in very vague terms about how the bill needs to “address” climate and can’t “go light.” It’s hard to take a stand without something to stand on, a climate provision so crucial that the bill can be portrayed as worthless without its inclusion. So far, they haven’t put anything forward.

The emerging deal doesn’t have 10 Republicans, and many Democrats—understandably—believe it never will, leaving reconciliation as the last best hope for an infrastructure bill. But even in that scenario, Manchin and Sinema could insist on bipartisanship. While progressives continue to harangue the two for believing Republicans would ever bargain in good faith, and pine for the moment they give up, the pressure may be counterproductive. Manchin and Sinema may be more determined than ever to proven right. On top of Manchin’s repeated odes to bipartisanship, Politico recently shed light on how much effort Sinema has put into crafting a compromise with Republican Sen. Rob Portman. If a bipartisan deal is forged with fewer than 10 Republicans, Manchin and Sinema could still get their end zone dance. They could tell Democrats they will only vote for their compromise package in reconciliation and refuse to go along with a larger partisan bill.

I can’t predict if the bipartisan group of 10 senators will be able to finalize a deal, nor can I predict if Manchin and Sinema are prepared to tell Biden he has to take the deal or get nothing. All I can say is that with a deal in hand, Manchin and Sinema will have the power to issue that ultimatum. The climate hawks, however, will have a tougher time gaining the leverage to play a similar game of hardball.

Bill Scher

Bill Scher is political writer at the Washington Monthly. He is the host of the history podcast When America Worked and the cohost of the bipartisan online show and podcast The DMZ. Follow Bill on Twitter @BillScher.