**Update–National Republican Senatorial Committee press secretary responds to the Bennet ad:

“After seeing the latest polls and recognizing that a strong majority of Colorado voters don’t support his big government, big spending agenda, it’s clear that Michael Bennet is desperate – it’s that simple. Voters should appreciate the irony that the same man who helped bankrupt the Denver public school system and advocated for government run health care while maxing out the government’s credit card is shameless enough to launch an attack along these lines. Michael Bennet is a left-wing extremist who has served as a loyal rubberstamp for the Obama agenda, and if he is sent back to Washington, he will continue to champion his party leaders’ priorities – not Coloradans’ best interests.”

A new TV ad from Sen. Michael Bennet’s campaign takes aim at his Republican opponent Ken Buck’s positions on Social Security, federal student loans, and abortion, while portraying Buck as an “extremist” — the label that has emerged as the Democrats’ primary weapon against Tea Party-backed candidates: