Senate Democrats are settling on an endgame for their bipartisan infrastructure negotiations: let them continue through the week after their Memorial Day recess, then forge ahead on their own if there's no deal.

Why it matters: President Biden said he hoped both parties could agree on a deal for roads and bridges before the holiday, but with the talks crumbling, Democrats are now readying to revert to Plan B — budget reconciliation — to get shovels into the ground.

• Sen. Bernie Sanders (I-Vt.) told Axios, “I think we are reaching the end of the period in which we have not seen serious Republican proposals. And sooner than later, we've got to make it clear that we are going forward to address the crises facing the market.”
• Asked if he’s started working on a potential backup package, Sanders nodded and said “Yes.” An aide said later he was referring to a budget resolution.

What we're hearing: Some Senate Democrats are privately looking at the week of June 7, when their chamber reconvenes after Memorial Day, as the last-ditch period for finding common ground.

• If the two parties are still as far apart on a deal by the end of that week as they are now, they predict Democrats will likely decide to move forward by themselves.
• This loose timeframe comes despite President Biden's deadline for having a infrastructure deal struck before they leave town this week.

Between the lines: "I think they message the hell out of the difference this week and back home next week, market-test their umbrage," a Senate Democratic aide said of Democratic leaders.

• White House press secretary Jen Psaki said Monday the administration is "not quite there" on giving Senate Majority Leader Chuck Schumer (D-N.Y.) the go-ahead on a fast-track bill.
• Nonetheless, Psaki emphasized this week is crucial, and said the ball is now "in Republicans' court."

The details: Schumer has begun meeting with Sanders, chairman of the Senate Budget Committee, as well as the Senate parliamentarian about the reconciliation process to understand his tactical options.

• Sanders has long said he thought reconciliation — with its 51-vote approval margin, rather than the standard 60-vote requirement — would be the ultimate vehicle for an infrastructure bill.
• "There will likely be a dual path where Schumer sets up the Budget Committee to be ready to go if talks fall apart," a senior Senate adviser told Axios.
• The Budget Committee would then set top-line numbers for the bill, and direct relevant committees such as the Senate Environment and Public Works and Senate Appropriations committees to report back with separate policy proposals.
• Schumer's policy team is expected to be the ones who eventually write the final legislation.

Timing: Congressional Democrats, particularly the progressive wing of the party, are eager to get moving on a bill.

• House Speaker Nancy Pelosi tentatively set July 4 as the date she wants infrastructure legislation approved in her chamber.

Be smart: Right now, all eyes are on whether Congress can pass Schumer's “United States Innovation and Competition Act of 2021.”

• It combines proposals from senators from both parties to better position the United States against China and other global competitors.
• Some Democratic lawmakers and their aides suspect that if this bill, which has involved a series of Republicans, can't pass, then the entire mood in the Senate will shift away from comity.
• Under that scenario, Schumer would likely have a harder time convincing his caucus to continue trying to work with Republicans, aides told Axios.