From the linked article:

At issue is whether income paid to wealthy investment fund managers should be taxed at the 15 percent capital gains rate or the upper income bracket, 35 percent and climbing. Proponents of the current system argue that the managers have a "carried interest" in the capital investments they oversee. Critics say it is ordinary income paid in exchange for the performance of services, and the managers often have very little skin in the capital game.

The House permits some leeway: allowing carried interest to be taxed at the capital gains tax rate to the extent that it reflects a reasonable return on invested capital. And after interviewing different coalitions with a stake in the outcome, Senate Finance staff is now looking at compromises that could address some complaints -- but still yield much needed tax revenue.

Hedge fund partners make for an easy political target today, but much of their trading is so short term that it doesn't qualify for the lower capital gains rate that applies to assets held more than six months. Private equity, publicly traded partnerships in the energy field and real estate partnerships are often affected more, especially given the strained state of commercial real estate. To win the needed votes, Baucus will have to look at options that ease the transition by perhaps imposing a midpoint rate -- between 15 percent and 35 percent -- or grandfather in some deals already made before a fixed date.

I don't know why, but I am imagining a whispered conversation between Baucus and those most likely to be affected: "stop worrying, boys...by the time we're finished here, this is going to be chump change for you - not gonna hurt one little bit."