The attempt to repeal Obamacare ultimately failed after getting stalled in the Senate. But the effort to scuttle the 2010 law inspired dozens of Democrats like Kim who have put the Affordable Care Act at the center of their campaigns and are using personal experiences to illustrate how a repeal would have hurt them.

Election losses

The decision by Democrats to take the offensive on health care marks a switch in tactics from 2010, when the party lost 64 seats and the House majority after passing the Affordable Care Act. To climb back they need to gain a net 23 seats to win back House control and the power to block key elements of President Donald Trump's agenda and any further attempts to roll back the law.

House Democrats named Kim, a former Obama administration national security aide, to their “Red to Blue” program for top tier candidates in Republican-held districts. His campaign reported raising $1.1 million through March 31. The nonpartisan Cook Political Report shifted its rating of the race between MacArthur and Kim on Friday from “likely Republican” to “lean Republican,” slightly less in MacArthur's favor.

The failed GOP repeal attempt gave Democrats a chance to promote popular aspects of the law — including its ban on jacking up rates for patients with pre-existing medical conditions. After years of attacks by Republicans, Obamacare gained majority public approval in a Gallup poll for the first time in April 2017. A Gallup poll last month found that the cost and availability of health care is Americans' top issue for the fifth year in a row.

MacArthur's amendment would have let states seek waivers to let insurers charge higher premiums for those with existing conditions and drop some benefits designated as “essential” under Obamacare, including maternity care.

Chris Russell, a campaign strategist for MacArthur, said his amendment “sought to make coverage of pre-existing conditions sacrosanct for all Americans and ensure essential health benefits remained the federal standard.” It wouldn't allow denial of coverage for a pre-existing condition, Russell said in a statement.

Higher premiums

But critics said it would have made premiums too expensive for people with health problems.

“I know exactly what happens when people lose their access to health care or health insurance,” said Kim Schrier, a pediatrician and one of five Democrats running to replace Republican Dave Reichert, who is retiring from his House district in central Washington state.

“I have my own pre-existing condition — type 1 diabetes,” Schrier said. “If I didn't have insurance through my company, I would be in that same situation.”

While repeated GOP efforts to repeal Obamacare have failed, Congress did vote in December to end a key component starting in 2019 — the requirement that almost all Americans obtain insurance or pay a penalty.

Premiums for 2019 are expected to be announced in October, just before voters head to the polls. The nonpartisan Congressional Budget Office forecasts a 10 percent increase for people who buy insurance on the individual market.

The individual market makes up just 7 percent of how Americans got their health care in 2016, compared to 49 percent of Americans with employer-sponsored coverage and 35 percent with Medicare or Medicaid. But the Affordable Care Act still drives the politics of health care. Bipartisan Plan Fails

A bipartisan Senate proposal to stabilize the Obamacare marketplace, sponsored by Republican Lamar Alexander of Tennessee and Democrat Patty Murray of Washington, failed in March over language restricting abortion funding.

Representative Ryan Costello, a Pennsylvania Republican who backed the Alexander-Murray plan and opposed the 2017 Obamacare repeal, said he believes voters will pay more attention to what Republicans are doing now.

“It's going to be much more on what are you doing, or how do you propose to lower costs, not how did you vote on a bill that never became law,” said Costello, who isn't seeking re-election.

But Democrats plan to make the argument to voters that Republicans should be held responsible for insurance costs because they control both chambers of Congress and the White House.

'Incredible contrast'

John Lapp, a Democratic strategist and former executive director of the Democratic Congressional Campaign Committee, said, “There's an incredible contrast with Republicans, who either their answer is to take away your health care, or do nothing and allow the health-care market to skyrocket.”

Priorities USA, a Democratic super-political action committee, cautioned party members in a memo last month not to lose track of the key issues that animate voters: the economy and health care.

While Trump's policies are “raising the cost of health care and driving up insurance premiums,” he gained ground on how the public viewed his handling of health care: from a 30-percentage-point net unfavorable rating to 12-point net unfavorable, said the memo prepared by the Hart Research Group and Global Strategy Group.

Medicare for All

National Republicans say Democrats are still responsible for health-care costs because they enacted Obamacare.

“Democrats are responsible for Obamacare and they've done nothing as it's destroyed our health care system,” said Jesse Hunt, a spokesman for the National Republican Congressional Committee, the House GOP campaign organization. “Their only answer now moving forward is to try to push a government-controlled, single-payer health care system that'll total $32 trillion.”

Such proposals have gained traction among Democrats. The House version of Senator Bernie Sanders's legislation to create a “Medicare for all” national health-care system has 122 Democratic co-sponsors. Liberal groups like the Progressive Change Campaign Committee, Democracy for America and Justice Democrats have endorsed more than three dozen Democrats running on nationalized, universal health care in Republican-held districts.

But the biggest shift for the party may be Democrats' willingness to defend Obamacare in competitive, Republican-held districts. Illinois GOP Representative Randy Hultgren's Democratic opponent, Lauren Underwood, is a nurse and former Department of Health and Human Services official who helped implement the health-care law during the Obama administration. Underwood beat six Democratic opponents in the state's March 20 primary.

“While the Affordable Care Act is not perfect — I don't think anybody is asserting that it is — American families have seen the benefits of having coverage options that are affordable,” Underwood said. “It touches everybody and they don't want to see it go away.”