Crossroads GPS greatly exaggerates the earnings of unionized government workers in a new TV ad attacking unions and Democrats, including President Obama.

The ad claims that government workers who belong to unions are paid “42 percent more than non-union workers.” But the very study cited by the ad says the gap is only 10 percent, once geographic differences are accounted for.

The 60-second spot was launched March 9 and is set to run nationally on CNN, CNBC and Fox News, according to a Crossroads GPS news release. The group said it would spend $750,000 to run the ad for one week. The ad is titled “The System.”

In the ad, the narrator says Democrats are “shutting down state capitals … to protect a system that pays unionized government workers 42 percent more than non-union workers.” On screen, the ad cites a Cato Institute study released last year.

It’s true that the Cato study was highly critical of public sector unions, and it contained a table showing that unionized workers in 2009 got total compensation (salary plus benefits) that was 142 percent of total compensation for non-union workers. But that was a national average, and as the study immediately makes clear, that 42 percent gap is not all or even mostly a result of the “system,” as this ad claims. It’s a result of geography. Here’s what the Cato study actually says:

Cato Institute, March 2010: [P]art of this union-nonunion pay difference stems from general labor market variations across states. States with generally higher wages tend to be more unionized. Analyses that hold constant such cross-state differences find that public-sector unions increase average pay levels by roughly 10 percent.

Context, Please

Other parts of the ad could benefit from added context. It starts by questioning an inflammatory remark made by Democratic Rep. Mike Capuano of Massachusetts at a gathering of Boston union members on Feb. 22. It shows a clip of the congressman saying, “you need to get out on the streets and get a little bloody when necessary.”

It’s true Capuano said that — but also true that he apologized for that remark the very next day. He issued a statement saying:

Rep. Capuano: I strongly believe in standing up for worker rights and my passion for preserving those rights may have gotten the best of me yesterday in an unscripted speech. I wish I had used different language to express my passion and I regret my choice of words.

Crossroads GPS accepts donations from business corporations and individuals. Though it does not disclose the identities of its donors, its political director, Carl Forti, says it raised and spent a total of $70 million during the 2010 elections in concert with its sister organization, American Crossroads. The two groups say they plan to raise $120 million for the 2012 elections.

Some Truth to It

Elsewhere the ad is accurate enough. President Obama is shown at a political gathering of the Service Employees International Union on Sept. 17, 2007, in Washington, D.C., saying: “[T]hey walked doors for me, they made phone calls for me, they turned out the vote for me.” Obama, then a freshman U.S. senator, was appealing for union support for his presidential campaign and recalling the support that helped elect him to Congress:

Obama, Sept. 17, 2007: That’s what you did with me in 2004, because I probably wouldn’t be standing here if it hadn’t been for the SEIU endorsement back then and the fact that all these folks sitting here right here, they walked doors for me, they made phone calls for me, they turned out the vote for me. And the reason they did it wasn’t just because they thought I was cute. The reason they did it was because we had fought together.

The ad also contains a lengthy clip of a farewell address given by Bob Chanin, the National Education Association’s general counsel, from July 2009. It shows Chanin saying that “NEA and its affiliates are effective advocates because we have power” stemming from “hundreds of millions of dollars in dues,” and not because “we care about children.”

Chanin’s entire 25-minute address can be seen on YouTube, where it was posted by the NEA July 6, 2009. The passage excerpted by the Crossroads ad begins at 21 minutes and 17 seconds into the speech. He goes on to say:

Bob Chanin: This is not to say that the concern of NEA and its affiliates with closing achievement gaps, reducing drop-out rates, improving teacher quality and the like are unimportant or inappropriate. To the contrary. These are the goals that guide the work we do.

That part, of course, was not included in the Crossroads GPS ad. Nor was Chanin’s reference to “right-wing bastards,” who he said were attacking the NEA.