Each has moved carefully with an eye on home-state voters. And inside the Senate, each has taken advantage of the political leverage newly available.
Nelson had been publicly signaling his intentions for more than a week, and his words presumably came as no surprise to Reid or the White House.
Reid, who spoke out strongly in favor of the change in antitrust treatment earlier in the fall, left it out of the bill he drafted over several weeks and unveiled on Wednesday.
Lincoln has been the most close-mouthed about her intention. As a committee chairman, she is the most powerful of the group. As the only one of the three seeking re-election next year, she is also the most politically vulnerable.
In public, she has asked that the bill be available for 72 hours before the vote occurs. In private, her demands have been more substantive, according to officials who did not describe them.
Clinton recently met privately with Senate Democrats, telling them that passing an imperfect bill was better than nothing. "We don't ever go to Washington with the idea that we're going to create a work of art," Lincoln said afterward. "It's got to be a work in progress."
A week ago, the agency thought better of the idea and shelved the plan in favor of further study. "I'm really thankful that they listened," said Landrieu, who had met with FDA Commissioner Margaret Hamburg to discuss the issue.
After meeting with Reid almost a month ago, she mentioned the "unique challenges Louisiana is facing in terms of Medicaid."
Landrieu can point to provisions in the legislation that are designed to attack all three problems.
They include Section 2006.
Should Landrieu decide to side with Republicans this weekend, she would also be voting to deny her state those funds.