In talking to party strategists in Washington and battleground states — mainly Democrats — there are two critical variables. One is the top of the ticket, or can the party’s nominee run better than Hillary Clinton did in states like North Carolina, Iowa, Arizona and Georgia? The other is will strong senate candidates, with sufficient money resources, emerge in several states?

Six months ago, the party anticipated top tier challengers like Steve Bullock in Montana and Colorado’s John Hickenlooper or some who ran dazzling races last year, almost pulling off big upsets, such Beto O’Rourke in Texas or Stacey Abrams in Georgia. Instead, those people are running for president or have specifically ruled out a Senate race.

In several of these contests, Democrats say they have solid backups. In Colorado — which is one of the top two Senate targets, along with Arizona — a dozen candidates already are running against incumbent Sen. Corey Gardner, a respected lawmaker who’s facing a tough slog in a blue state where Trump is unpopular. Democrats believe they have a good chance to win if they nominate someone like Mike Johnston, a former state senator and Obama education adviser — less so if a left winger wins the primary.