Senate Republicans say they are increasingly focusing their fire power in the two-step infrastructure fight on a chaotic budget brawl that will tee up Democrats’ $3.5 trillion spending plan. 

Senate Democrats want to pass two things before letting senators leave for their summer break: a roughly $1 trillion bipartisan infrastructure deal and a budget resolution that lets them bypass Republicans later this year on a $3.5 trillion spending plan that includes top Democratic priorities like expanding Medicare, combating climate change and immigration reform. 

With Republicans viewing passage of the bipartisan agreement as increasingly inevitable — even as they haggle over potential changes — they say the real fight will be over the budget resolution. 

“That’s one that members really want to dig in and fight on,” said Sen. John Thune (S.D.), the No. 2 Senate Republican. 

Sen. Mike Braun (R-Ind.) has opposed the bipartisan infrastructure deal but called it passing a “fait accompli” and that the fight over the budget was the “main event.” 

“I think the real action will be on reconciliation,” he said, referring to the process Democrats are using to pass their budget and spending plan. 

Democrats will need total unity as they take two steps to get their $3.5 trillion spending plan through the Senate. 

In the first step, the party must pass a budget resolution that includes the topline and drafting instructions. Senate Democrats are expected to try to take that step as soon as next week and appear confident that they will have total unity in their 50-member conference. 

They’ll then need to negotiate and write the spending plan itself. It’s less certain they’ll have all 50 Democrats on the same page for that vote.

Both steps spark what is known as a vote-a-rama in the Senate: a chaotic, hours-long session where any senator can force a vote on any proposal. 

It’s a prime opportunity for GOP senators to force Democrats to take politically difficult votes ahead of next year’s midterm election. 

“Let’s just say this process should be painful,” Thune added.  

Members of GOP leadership knocked the $3.5 trillion Democratic plan as a "reckless tax and spending resolution," and Thune is going to lead a press conference Wednesday to ramp up GOP messaging heading into the budget fight. 

Republican opponents of the bipartisan deal haven’t thrown in the towel. 

Heritage Action, a conservative group, is urging Republicans to vote against the bill, calling it “bad policy” and “bad process.” A group of conservative senators also blasted the way the bipartisan group proposes to pay for its spending. 

And Republicans are still trying to make changes to the bipartisan deal. As of Tuesday evening nearly 300 amendments had been filed with Republicans proposing changes to the broadband and energy sections as well as how the bipartisan group proposes paying for their bill. 

They warned Senate Majority Leader Charles Schumer (D-N.Y.) against quickly wrapping up debate, saying that the first test vote shouldn’t come up until at least Saturday. One scheduling curveball is that several senators are expected to fly to Wyoming to go to a funeral service for former Sen. Mike Enzi (R-Wyo.) on Friday. 

But they also made clear that they view the fight over the bipartisan deal, which several of their members support and helped craft, and the budget measure differently. 

“The infrastructure package stands on its own by itself,” McConnell said, repeating publicly a message he gave privately to Republicans last month. 

And Republicans say they think it’s just a matter of when the bipartisan agreement will pass the Senate, either this weekend of next week.

“I think it passes, I think the question is when it passes and what else is in it that’s not in it yet,” said Sen. Kevin Cramer (R-N.D.). 

Sen. Mike Rounds (R-S.D.) added that there was a “real high probability” that the bipartisan deal passes the Senate. 

Braun and Sen. John Cornyn (R-Texas), neither of whom have supported the bipartisan deal so far, predicted it passes.

And Thune, McConnell’s No. 2, said there was a “pretty good” chance that it would pass and is already talking to Schumer about the timeline for wrapping up the bill. But even if it was a “fait accompli,” he added, Republicans still wanted “integrity in the process,” meaning the ability to get some amendment votes. 

The core group of bipartisan negotiators have a deal amongst themselves to vote against any amendments that they believe threaten the ability for their bill to get the 60 votes needed to ultimately pass. 

And Republicans floated that having the budget fight coming up, where they can force any vote they want, takes off some of the pressure to go all in on amendments to the bipartisan deal, where getting an amendment vote requires buy-in for every member and is subject to intense negotiation. 

Asked if he thought the vote-a-rama meant fewer political amendments to the bipartisan deal, Thune added: “I think that’s right.” 

“I don’t think you’re going to find the hot button issue amendments. I think that probably comes next week or whenever we get on the budget resolution,” Thune said. “Any vote-a-rama lends itself, by both sides, to uses for political purposes.” 

A GOP senator predicted that the bipartisan deal “will benefit” from the upcoming vote-a-rama on the budget and result in “less of an appetite” for a laundry list of controversial amendment votes on the bipartisan bill. 

“Because if someone has a political point that they would like to make … I think it’s more likely for Republicans, and for Democrats perhaps, that it would be done in vote-a-rama,” the GOP senator said.