Sorry, but we are currently unable to access blog posts from http://blog.prospect.org/blog/ezraklein/2009/02/what_obamas_budget_does_and_do>Ezra Klein speculates on what Congress might identify:

..according to both members of Congress and the administration, that ambiguity obscures a specific solution under examination: The employer tax exclusion...

...This is a particularly tricky policy for the Obama administration to propose because they brutalized John McCain for suggesting much the same thing. McCain, they said, was planning to tax employer health care benefits for the first time in history.

Hypocrisy? Maybe a bit. But not on the merits. The problem with John McCain's health care plan, as I and others argued at the time, was not that it eliminated the employer tax exemption, but that it put nothing in its place. The McCain plan removed the exemption and offered subsidies for the existing individual market in return. That was worse than nothing. The strategy being discussed between Obama and congressional Democrats caps the exemption and use the money to build a better group market.