Last year, as aspiring Republican candidates for Senate gathered for a forum, Ken Buck took a strong stand on religion, saying he disagreed with the concept of the separation of church and state because it is “not written into the Constitution.”

That view, revived by the liberal ThinkProgress with just a week to go before the election, was prompted by unverified online claims that President Barack Obama has called the White House “Christmas tree” a “holiday tree” instead. (“It’s just flat wrong in my mind,” Buck said of the claims.) The left-leaning Huffington Post website responds that Buck’s statement shows he disagrees with “one of the bedrock principles of American society.”

Noting recent polls showing Buck in a tight race with Democratic U.S. Senator Michael Bennet, Politico thinks the Democratic effort to chip away at Buck’s veneer is taking a toll. “They have roasted Buck for his comments on gays, a case of alleged rape he handled as a prosecutor, and skepticism about global warming,” Politico writes, attributing the “recycled” video clip of Buck saying he disagrees with the concept of “the separation of church and state” to Bennet’s campaign.

Buck campaign manager John Swartout says the Bennet camp utilized a “sophisticated operation of blogs and other outlets” to focus media attention on Buck’s verbal gaffes. “We don’t have Huff Post, ThinkProgress, Colorado Pols,” Swartout says.

Still, Buck’s church-state comment recalls a similar, more recent one made by another tea-party darling, Delaware Republican U.S. Senate candidate Christine O’Donnell, who said during a televised debate, “Where in the Constitution is the separation of church and state?” (via CBSNews).