Senator Ben Nelson (D-NE) has scheduled a press conference to take place later this afternoon, reportedly to announce his intent to retire from Congress.

The 70-year old Nelson has been at the center of major ad buys by nearly everyone in both parties as well as a few outside groups, and is thought to have become one of the most endangered Democrats in the Senate. In the upcoming 2012 election , 23 Senate Democrats will have to defend their seats, as opposed to just 10 Republicans.

Due to the high-stakes of the 2012 election and the strategic need for Democratic wins in the Senate should President Obama see a second term, many party officials have been lobbying Nelson to stick around for at least one more term. However, Nelson himself has been hinting for weeks that a heavy decision regarding his political future has been in the works, and would be announced before the year’s end.

At this time, it is not known who the Democrats would select to run in Nelson’s place. There have been a few suggestions that former Nebraska Governor Bob Kerrey, himself a former Senator, could be the party favorite.

At this time, Kerrey has refused to say whether or not he would consider running for Nelson’s seat, but also hasn’t ruled it out.