WHITE HOUSE, LABOR STRIKE PRELIMINARY DEAL…. Earlier this week, health care reform appeared stalled, with progress nowhere in sight. Over the last 24 hours, its fortunes have improved considerably.

The White House has reached a tentative agreement with labor leaders to tax high-cost health insurance policies, sources said Thursday. The agreement clears one of the last major obstacles on the path to final passage of comprehensive health care legislation.

White House press secretary Robert Gibbs said health care negotiators are “very, very close” to an overall deal and hope to have resolved most of their differences by day’s end. But White House officials privately cautioned that their optimism does not mean that a final health care deal will be formally announced Thursday.

Four labor negotiators briefed lawmakers on the parameters of the deal at a luncheon at the Capitol. Lawmakers said the agreement would raise the cost of unusually generous health policies and ignore secondary coverage, such as vision and dental plans. Health plans negotiated as part of collective-bargaining agreements would be exempt for two years after the 2013 effective date, giving labor leaders time to negotiate new contracts.

The NYT‘s David Herszenhorn has more on the structure of the compromise and who it would affect.

Rob Andrews (D-N.J.) said of the excise tax impasse, “This was a very critical issue that had to be resolved, and I think it has been.” That said, Rep. Joe Courtney (D-Conn.), a leading opponent of the provision, said he has not yet approved any deals.

Robert Gibbs told reporters today that a final day may not be ironed out until early next week, but that yesterday’s marathon discussions generated “tremendous progress.”

The wait may be even shorter than Gibbs suggested — some House leaders hinted earlier that a bill may be sent to the Congressional Budget Office for a score by Saturday.

We’re close enough to the finish line that the House Democratic leadership reminded observers today that it will put the final reform bill online for 72 hours before the chamber votes on it, so it can be reviewed by lawmakers and the public.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.