“These are certainly different times,” says Curt Anderson, a GOP strategist whose firm is involved in a lot of House races this year. One reason for Republican caution, Anderson explains, is that this year it will be easier for moderates to cast an anti-Trump vote than it was in 2016.

“In 2016, people who for whatever reason didn’t like Trump had to swallow hard and vote for Hillary to show their displeasure,” Anderson explains. “That’s some nasty castor oil right there, and many refused to take it. The fear in 2018 for Republicans is that voters who don’t like Trump can send him a message — by voting against his party — and this time they don’t have to vote for Hillary in order to punish Trump.”

Given that, Anderson says, “I do think Trump’s approval numbers will matter this fall … [and] already this year we have seen small shifts that have pretty dramatic consequences.”