BUSTED: Four GOP senators caught running ads that lie about preexisting conditions

On Thursday, NBC News dissected the false claims of four Republican senators who are claiming they will protect insurance coverage for people with pre-existing conditions.

Sen. Cory Gardner (R-CO), for example, is running an ad that says "Cory wrote the bill to guarantee coverage to people with pre-existing conditions — forever. No matter what happens to Obamacare." But, wrote Sahil Kapur, the law he sponsored only prohibits insurers from charging more or denying certain procedures — it would still let insurers deny people coverage altogether, which the ACA does not.

Similarly, Sen. Martha McSally (R-AZ) is running an ad saying, "[Democratic opponent] Mark Kelly's attacks on me are false. And they're shameful. Of course I will always protect those with preexisting conditions" — even though she voted for a 2017 bill, the American Health Care Act, to demolish the ACA's pre-existing condition protections.

Meanwhile, Sen. David Perdue (R-GA) has an ad that cites his sister who survived cancer, and says "Health insurance should always cover pre-existing conditions. For anyone. Period," and an ad for Sen. Steve Daines (R-MT) says "Steve Daines will protect Montanans with pre-existing conditions." But both Perdue and Daines voted to advance the Better Care Reconciliation Act, which would have allowed "non-compliant plans" that exclude pre-existing conditions to compete with "compliant" plans — something experts say would ultimately blow up the health care market and make compliant plans unaffordable.

Public opinion on the ACA has dramatically shifted since President Donald Trump's election, with large majorities now supporting the law's benefits and protections — forcing many Republicans who spent years voting for repeal to walk back their positions.