The particulars may have varied, but the source of the frustrations were the same: Democrats have sought to pass expansive new legislation that is flatly opposed by Republicans using a razor-thin 50-50 Senate majority, with decisive votes cast by Vice President Harris.

Party leaders, including Majority Leader Charles E. Schumer (D-N.Y.), did not narrow lawmakers’ ambitions to match their margins, and they have watched lone-wolf senators dictate the pace and scope of legislation, with two in particular — Sens. Joe Manchin III (D-W.Va.) and Kyrsten Sinema (D-Ariz.) — playing a leading role in reining in their party’s big dreams.

By Friday afternoon, the year appeared poised to end on an especially ignominious note. Manchin completely upended Democrats’ plans for the domestic policy bill, known as Build Back Better, questioning its structure and efficacy, forcing party leaders to punt consideration into January. Sinema, meanwhile, appeared to be an intractable obstacle to a rules change, thus leaving no feasible path to passing the voting bills, which Republicans have fiercely opposed as partisan attacks on state sovereignty.