Who is behind the Tea Party organization pushing for a GOP upset in Delaware?

The Tea Party is going for another Republican scalp, this time in Delaware. But wait. Is it, in fact, the Tea Party?

Christine O’Donnell has become the latest virtually unknown candidate to zoom out of seemingly nowhere – just like in Massachusetts, Nevada, Utah and most recently Alaska – and now threatens to upend the more established GOP candidate, Rep. Mike Castle, in Delaware’s Republican Senate primary.

With each successive upset, the national spotlight on Tea Party insurgencies has grown more intense. And the hotter the national focus, the simpler the narrative has become: the Tea Party has backed an upstart candidate. Voila.

The problem is, the group that has spent money to produce the upsets — $560,000 in Alaska with plans for $250,000 in Delaware before next Tuesday’s primary — is only one of a handful of national groups that have claimed the Tea Party mantle.

In addition, the Tea Party Express is also maligned by the most prominent other national group, the Tea Party Patriots, as being a group of political operatives out to line their own pockets with the donations of unknowing conservative grassroots activists.

So who is the Tea Party Express? In short, it is a Sacramento-based national political action committee run by two veteran political operatives from California but staffed largely by political novices. Here’s a look at the key people involved in running the organization:

Sal Russo: The 63-year old Russo is the most senior principal at TPE, along with his 37-year old protégé, Joe Wierzbicki. Both have spent most of their careers in California politics, advising Republican candidates and spearheading political and public relations campaigns. Russo founded Russo, Marsh and Rogers, a GOP public relations firm in Sacramento, and Wierzbicki also works for the organization. But Russo gives true meaning to the term “veteran political operative.” He got his start in politics when he volunteered for Ronald Reagan’s 1966 gubernatorial campaign. He briefly came to Washington when Reagan was elected president, but “didn’t like what happened to his own head” in the nation’s capital, said Mark Williams, a radio talk show host who was with TPE until recently.

But Russo worked on Reagan’s 1984 reelection campaign. He has also been involved with national elections in New York, U.S. presidential campaigns, and even PR campaigns in foreign countries. Russo helped coordinate a media campaign in the Ukraine to push for a presidential referendum in 2004. In the California political world, “there’s a sense that, ‘can you believe that Sal Russo has kind of reinvented himself as the Tea Party Express guy?’” said one GOP political operative with years of experience in the state. “There’s that sense of, ‘You know who runs the Tea Party Express now? Russo. Wow. Russo?’ He’s been around in California politics for so long…He’s a California Republican.”

Russo likes to keep a low profile. His picture on the TPE website is at the very bottom, below figures who are much more peripheral in the organization. But he’s well-known to even the most high-profile Republican leaders. “He’s a hoss,” said Mississippi Gov. Haley Barbour, who said he’s known Russo for 40 years.