Colorado’s U.S. senator and the state’s remaining candidate in the race for president, Michael Bennet, continued Friday to hammer on the Medicare for All proposal being talked up by the favorites of the Democratic base.

Sen. Elizabeth Warren officially rolled out her Medicare for All plan Friday morning, an initiative that would cost $52 trillion over the next decade, including $21 billion in new federal spending.

RELATED: Democratic Sens. Michael Bennet, Tim Kaine unveil bill to create ‘Medicare-X,’ a public-option health plan

Bennet, a very long shot to make it to the White House, accused Warren of playing political shenanigans. 

“Voters are sick and tired of politicians promising them things that they know they can’t deliver,” said Bennet in response to the Massachusetts senator’s health care plan, one also supported by fellow top-tier candidate Sen. Bernie Sanders.

“Warren’s new numbers are simply not believable, and have been contradicted by experts. Regardless of whether it’s $21 trillion or $31 trillion, this isn’t going to happen, and the American people need health care.”

Bennet, instead, plugged the public option plan he and other moderate Democrats favor, called Medicare X, which would allow Americans to buy a government plan or keep their private insurance.

“My public option plan, Medicare-X, is the best way to give families a choice, cover everyone in three years, and lower costs,” Bennet said in a statement,. “And it doesn’t cost a cent in new taxes.”

As Bennet continues to criticize Warren’s plan, it raises questions about a possible alliance with another front-runner, former Vice President Joe Biden, if Biden reaches the point where he is looking for a running mate or Cabinet member.

Biden also has been critical of the vague costs and viability of the Medicare for All plans pitched by Warren and Sanders.

“When you’re running to take on the most dishonest president in American history, Senator Sanders and others who back Medicare for All have to preserve their credibility,” Biden deputy campaign manager Kate Bedingfield said this week.