‘Medicare for all,” is the rallying cry on ObamaCare from congressional Democrats, led by Brooklyn’s Rep. Anthony Weiner, who insist the medical program for seniors proves that a single-payer system works, and works well.

Alas, it proves nothing of the sort.

Indeed, Weiner & Co. may want to check out the numbers in an explosive new federal report.

According to the survey, Washington paid more than $47 billion in questionable or fraudulent Medicare claims in FY 2009 — fully 12.4 percent of the $440 billion program’s annual budget.

The Centers for Medicare and Medicaid Services report says Medicare fraud for the first nine months of 2009 increased at a rate nearly triple the previous year.

Not that fraud is necessarily on the rise: New methodology uncovered previously undisclosed improper payments — meaning that Medicare fraud likely has been rampant for years.

Moreover, according to Sen. Charles Grassley (R-Iowa), federal watchdogs received 30 fraud warnings over the previous years from inspectors, including of organized crime scams and physician kickbacks — and simply ignored them.

None of this should surprise: Critics have been warning of widespread Medicare fraud for at least two decades.

Medicare’s trustees have warned that the program’s trust fund will be empty within a decade, because spending far outstrips the taxes that support it.

Even a proposal by the Department of Health and Human Services to root out Medicare fraud still sees an overpayment rate of 8 percent in 2012 — and that’s if the program works exactly as planned.

Understanding how Medicare works, says Weiner, “should help us visualize what an actual public plan [under ObamaCare] would look like.”

Indeed it does.