President Obama to address Sen. Bennet's tele-townhall Tuesday evening

President Obama added a campaign appearance of sorts for Sen. Michael Bennet (D-Colo.) to his schedule Tuesday. 

The president will address a tele-townhall Bennet is hosting tonight at 8:15 p.m., according to his official schedule.

Bennet is facing former Colorado House Speaker Andrew Romanoff (D) in a Senate primary that has tightened considerably over the past few weeks. The latest polling out of the state has Romanoff and Bennet in a dead heat after months of Bennet leading. Voters go to the polls August 10.

In a twist, the Senate primary pits Obama and former President Clinton against one another. Last month, Clinton endorsed Romanoff and penned a fundraising e-mail for him even though the White House had already weighed in on behalf of Bennet.  

The two Democrats are spending heavily down the stretch. Bennet just loaned his campaign $300,000, while Romanoff sold his house last week to lend his campaign extra cash.

Bennet is trying to avoid becoming the latest sitting senator to lose a primary. Earlier this year, Sen. Arlen Specter (D-Pa.) lost his primary challenge to Rep. Joe Sestak (D). And, in Utah, Sen. Bob Bennett (R) lost out on his party's endorsement at the state convention.

The White House has a mixed record in Senate primaries this campaign season. It backed Specter in Pennsylvania and Sen. Blanche Lincoln (D) in Arkansas, where the incumbent barely survived a primary challenge from Lt. Gov. Bill Halter. 

Obama was in Colorado in February to fundraise for Bennet.

No word from the Bennet camp as to how the president's involvement in the tele-townhall event came about, but perhaps the campaign just asked for the White House help.