(Updated from 9:39 a.m. ET)

Vermont Sen. James M. Jeffords confirmed this morning that he will leave the

Republican Party

to become an independent, giving the

Democrats

operational control in the

Senate

.

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Vermont Sen. Jeffords Leaves GOP, Confirming Speculation

Jeffords' move ends the 50-50 split in the Senate between the GOP and the Democrats, who will now have a one-seat edge over the Republicans. The Democrats will assume the chairmanships of the various Senate committees, putting them in a position to schedule legislative action, prioritize hearings, call for investigations and potentially make federal appointments more difficult. The one exception will probably be the Committee on Environment and Public Works, which would be led by the now independent Jeffords. South Dakota's Tom Daschle is in line to replace Mississippi Sen. Trent Lott as majority leader.

Additionally, Jeffords, who was known as a moderate Republican, said he would align more closely with the Democrats by joining that party's caucus now that he has the independent label.

In recent days, as Jeffords' plans became known, analysts speculated that the senator's defection from the GOP could derail parts of

President Bush's

agenda. Market watchers indicated that the pharmaceutical sector and energy exploration companies would be among the groups potentially hurt the most if the Democrats take over the Senate, while alternative energy suppliers and mortgage finance companies could benefit from the power shift.

Yesterday,

TheStreet.com

took

a deeper look at what Jeffords' defection from the Republican Party could mean for a variety of sectors.

The Senate will now have 50 Democrats and 49 Republicans, in addition to the independent Jeffords.