WASHINGTON (CNN) - Leaders of the liberal Congressional Progressive Caucus in the House sent a letter Monday to Health and Human Services Secretary Kathleen Sebelius, telling her "we stand in strong opposition to your statement that the public option is 'not the essential element' of comprehensive reform."
Responding to Sebelius' comments on CNN's State of the Union Sunday, the Democratic lawmakers warned that a health care bill without a public plan won't pass the House.
"Americans deserve reform that is real – not smoke and mirrors. We cannot rely solely on the insurance companies' good faith efforts to provide for our constituents," wrote Democratic Representatives Raul Grijalva D-Arizona, Lynn Woolsey D-California and Barbara Lee D-California.
"To take the public option off the table would be a grave error; passage in the House of Representatives depends upon inclusion of it."
Although the letter is only signed by the co-chairs of the congressional progressive caucus and the chairwoman of the Congressional Black Caucus, they also included a letter signed by 60 Democrats before Congress left for recess, which says a final proposal for the president's signature must contain a public option.
Because weekend comments from both Sebelius and the president himself have infuriated liberal Democrats, House Speaker Nancy Pelosi was forced to release a statement reaffirming her commitment to bringing a bill before the House with a public option, which is scheduled for September.
"There is strong support in the House for a public option," said the House Speaker, "a public option is the best option to lower costs, improve the quality of health care, ensure choice and expand coverage." (link to post on full statement sent earlier)
In fact, several House Democratic leadership aides tell CNN they believe the leaders of the House progressive caucus are right – they likely do have enough votes to block a health care reform bill in the House if it doesn't include a public option.
The problem for the White House is that in the Senate, Democratic leaders have believed for some time that they can't pass a health care bill with a public option – primarily because of concern not just from Republicans, but among conservative Democrats who worry it could hurt private insurance companies.
Senior Democratic sources tell CNN they believe the challenge is bigger in the Senate, and one senior Democratic source with knowledge of White House strategy told CNN many believed the timing was right for the White House to show it is "willing to be reasonable."
To that end, Senate Majority leader Harry Reid released a statement Monday through a spokesman echoing the weekend sentiment from President Obama and his HHS Secretary.
"Senator Reid supports bipartisan health care reform that cuts costs, and provides quality coverage to all Americans, and he recognizes there are different proposals on the table to accomplish this goal. He also knows that 60 votes will be needed to get anything done, which is why he will continue to assess the votes until Congress returns in September," said spokesman Jim Manley.