Democratic Congressional Campaign Committee Chairman Chris Van Hollen (Md.) on Monday said the party’s ongoing presidential nomination fight was in key battlegrounds “the storm cloud on the horizon” facing House Democrats between now and midsummer.

“This is the biggest unknown variable in Congressional races,” Van Hollen told reporters at Monday’s Christian Science Monitor breakfast.

With so much in flux, Van Hollen said that it’s too early to predict how many seats House Democrats expect to net this fall, but he warned against “irrational exuberance” in setting the bar too high.

“It’s important to temper those expectations,” he said.

Van Hollen would confirm that the DCCC is focusing on as many as 75 seats and said that predictions of a possible five- to 10-seat Democratic pickup was a “possible forecast, but warned against drawing conclusions before Democrats have their candidate.”

— Matthew Murray