If McAuliffe doesn’t pull out a win, some pessimistic Democrats privately predicted a “collapse” on Capitol Hill, where party leaders are already struggling to unite sparring progressives and centrists around a roughly $2 trillion social infrastructure package. Meanwhile, the Senate-passed $550 billion bipartisan infrastructure bill is sitting on the shelf because the votes aren’t there in the House, much to Virginia Democrats’ irritation.

That bill is stalled out because Pelosi and other senior Democrats have yet to clinch a deal on the social spending bill with two key holdouts, centrist Sens. Joe Manchin (D-W.Va.) and Kyrsten Sinema (D-Ariz.). And despite public pronouncements of action by the end of October — when Congress will again be forced to address expiring highway and transit programs — Democrats appear far from even an outline of an agreement…

“Terry losing is catastrophic for the agenda,” said one longtime Democratic aide, summing up the views of the party’s most vulnerable members on condition of anonymity.

Predictably, most Democratic lawmakers did not want to go on the record to forecast what would happen if Youngkin stunned their party in a reliable state and won. Democrats control both of the state’s legislative chambers, as well as every statewide elected office, but Bob McDonnell’s resounding gubernatorial win in 2009 demonstrated how hard national momentum swung away from Democrats as they tried to clinch the Affordable Care Act.