WASHINGTON – Democrats on Thursday defended their assertion that Republicans "voted to end Medicare," after a respected fact-checking organization rated it among the most deceitful political lies.

The claim came in an ad attacking House Republicans for voting last Friday to pass a budget plan that erodes Medicare over time. The spot depicted seniors as being forced to mow lawns and sell lemonade to pay their medical bills under the GOP program.

"There is no doubt that Medicare -- a health insurance program for seniors --  would end under the House Republican plan and, according to the independent Congressional Budget Office, health insurance costs for seniors would rise," Democratic Congressional Campaign Committee spokesman Jesse Ferguson told Raw Story.

The comment was a response to the Pulitzer Prize-winning PolitiFact, which examined the DCCC claim that the GOP program would "end Medicare" and decreed it a flagrant lie, or "pants on fire."

"Democrats, including Obama, have said the plan would end Medicare 'as we know it,' a critical qualifier. But the 30-second ad from the DCCC makes a sweeping claim without that important qualifier," PolitiFact explained, calling the DCCC claim a "major exaggeration."

The GOP plan drastically transforms Medicare in the long-run. It would remain in tact for the next ten years, but Americans turning 65 in 2022 and after would not be allowed to enroll in the single-payer program, and would instead be given vouchers to buy private insurance, whose real value would erode over time.

The nonpartisan CBO projected that medical expenses will grow for seniors under the proposal, diminishing the value of the safety net over time.

"The plan would essentially end Medicare," was how the Wall Street Journal reported it.

In response to questions from Raw Story, PolitiFact editor Bill Adair defended the website's rating as "the right call" but said he respects those who disagree.

"As our story states, people watching the ad get the impression that seniors need to come up with an extra $12,000 right now to pay for their health care. That is not the case," he wrote in an e-mail. "The Republican proposal is still a proposal and no actual changes to Medicare have been implemented. The ad suggests otherwise."

Asked whether PolitiFact would have rated the DCCC claim true if it said the GOP plan would "end Medicare as we know it in 10 years," he said: "I can't give you an exact ruling since we haven't rated that particular claim, but that is definitely more accurate way to describe the plan."

Watch the DCCC ad below.

[h/t Brian Beutler at TPM]