CEDAR RAPIDS, Iowa — Democrats used a bus emblazoned with the words “Drive for our Lives” to gin up opposition to vulnerable House Republicans who voted against ObamaCare with the aim of upending the GOP’s majority in next year’s midterm elections.

The vote to repeal and replace the health care law looms large for 21 GOP lawmakers, including Iowa Reps. David Young and Rod Blum. They represent competitive congressional districts where Democrat Hillary Clinton won or came close in last year’s presidential election.

The collapse of the yearlong Republican quest to dismantle ObamaCare has been a bitter pill for House Republicans who voted for the legislation in May only to see the drive fall apart recently in the Senate when the GOP failed to muster enough votes.

Now all that some lawmakers have to show for the politically tough vote is the word “mean” — President Donald Trump’s description of legislation that would have made deep cuts in Medicaid, allowed states to opt out of coverage for essential benefits and knocked 23 million Americans off insurance.

The bus motored into Iowa on Friday, stopping in Cedar Rapids, the largest city in Blum’s eastern Iowa district, where Diane Peterson urged Blum to listen to his district’s independent voters, who outnumber those affiliated with either major party.

“Of course there are things in the ACA that need fixing,” said Peterson, referring to the Obama health law’s name, the Affordable Care Act. The 61-year-old Democrat and coffee shop owner from Hiawatha added, “But Republicans now need to reach out.”

While Blum has allied himself with the House’s conservative Freedom Caucus, Young angered conservatives when he initially opposed a House GOP health care bill, then weeks later swung behind it. Independents were frustrated with the two-term congressman’s embrace of a partisan approach to repealing ObamaCare.

“David Young is not as conservative as some would like here in southwest Iowa,” said Council Bluffs Republican David Overholtzer, a 56-year-old accountant.

“Things need to get done,” said Jeff Jorgensen, a western Iowa Republican county chairman. “He’s doing OK, but his chances for re-election are tied to Trump’s popularity.”

The Des Moines Register’s Iowa poll last month showed Trump’s disapproval climbing to 52 percent. The increase was driven largely by independents.

Independents, who hold sway in Young’s politically diverse district, want a bipartisan approach to health care.