Kyrsten Sinema is threatening to hold Biden's agenda hostage, report says. She wants to pass the bipartisan roads-and-bridges bill now.

• Sinema won't back larger spending bill until the House passes infrastructure bill, Reuters reported.
• The Arizona Democrat's opposition would effectively stall the party-line bill.

Democratic Sen. Kyrsten Sinema of Arizona is threatening to torpedo Biden's agenda, telling a group of fellow moderate Democrats in the House of Representatives that she won't support a multitrillion-dollar reconciliation package until Congress passes the $1 trillion infrastructure spending bill first, Reuters reported on Thursday.

Reuters cited a source briefed on the meeting in its report about the request by Sinema, a key moderate whose resistance to the reconciliation deal has stalled Biden's signature legislation.

In the split 50-50 Senate, Sinema wields power to prevent legislation from moving forward given that Democrats are using a process known as reconciliation to muscle the bill through, relying on their thin majorities. It allows the bill to be approved with only a simple-majority vote, bypassing united Republican opposition and the usual 60-vote threshold in the Senate. But Senate Democrats must stick together for the plan to clear the upper chamber.

The $3.5 trillion budget-reconciliation package is a staple of President Joe Biden's agenda, packed with priorities such as affordable childcare, an expansion of Medicaid and Medicare, and expanded child tax credits. But Sinema and fellow moderate Sen. Joe Manchin of West Virginia are holding out on the bill as a separate bipartisan infrastructure package is discussed in the House.

House progressives, meanwhile, refused to pass the infrastructure deal unless the reconciliation package was approved at the same time. A progressive rebellion late last month forced House Speaker Nancy Pelosi to pull the bill from the floor since it was on the verge of failing.

This week, progressives criticized Sinema for refusing to lay out what she seeks in the safety-net bill. Sen. Bernie Sanders of Vermont said on Tuesday that "the time is long overdue" for Sinema and Manchin to describe their priorities. Now, Sinema seems determined for the infrastructure bill to pass first.

Representatives for Sinema did not immediately respond to a request for comment by Insider.