Up until this point, health care has faced the most difficulty in the Senate, while things have gone relatively smoothly in the House. Not anymore. The House Democrats were set to release their health care bill today, and begin the process of marking it up, or rewriting it, on Monday. But Roll Call reports that the legislation has now been “delayed indefinitely” because of a letter sent by moderate Blue Dog Democrats demanding major changes. According to CNN, 40 of 52 members of the Blue Dog coalition signed the letter, a big enough chunk to endanger the legislation if Republicans stick together. The major concern of the Blue Dogs is the design of the government-run plan. While not being dead against it, they are opposed to setting the reimbursement rates at the very low Medicare levels. But what makes things really tricky is that the House Progressive Caucus, which boasts 80 members, has said it wouldn’t support a plan unless it included a “robust” government plan — which means one modeled after Medicare. Last month, I wrote at length about how this dynamic could rip apart President Obama’s health care push.