(CNN) President Donald Trump issued a warning to fellow Republicans to support coverage of pre-existing conditions with less than 20 days until the midterm elections.

"All Republicans support people with pre-existing conditions, and if they don't, they will after I speak to them. I am in total support. Also, Democrats will destroy your Medicare, and I will keep it healthy and well!" he tweeted Thursday afternoon after departing the White House for a campaign swing out West.

The tweet is in line with a familiar refrain from Trump's recent campaign rallies and even dating back to his debates during the Republican primary. However, it's not consistent with his administration's actions and policies.

Earlier this month, a Democratic measure aimed at eliminating short-term health care plans that don't have to cover pre-existing conditions failed in the Senate . Maine Sen. Susan Collins was the sole Republican to vote for the measure. The resolution was aimed at rebuffing a Trump executive order unveiled in August that made it easier to buy these plans.

Short-term health care plans don't have to adhere to the Affordable Care Act's regulations that protect people with pre-existing conditions. These plans can deny coverage or charge higher premiums to Americans based on their medical histories. And they don't have to provide comprehensive coverage. The Trump administration made it easier to buy these plans -- allowing people to buy coverage for just under a year, versus the 90-day limit imposed by the Obama administration.

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