A Senator Fights Back - NYTimes.com It is dangerous to challenge the funnel cloud of corporate and right-wing political advertising this year, but Senator Claire McCaskill, Democrat of Missouri, has decided to fight back. She is running commercials that talk directly about the ads trying to prevent her re-election. "They're not from around here, spending millions to attack and attack," said one of her recent commercials, showing clips from the opposing ads that have become ubiquitous in her state. But what they're doing to Claire McCaskill is nothing compared to what their special-interest agenda will do to you. It will be an uphill fight. Republican interest groups are outspending Ms. McCaskill and other Missouri Democrats by a 7-to-1 ratio; Ms. McCaskill herself is being outspent by 3 to 1. Though she has raised nearly $10 million, the amount could be dwarfed by the unlimited money at the disposal of Republican-oriented groups. Once again, as in 2010, Congressional races will be the elections most affected by unregulated slush-fund money. Though "super PACs" and secretive independent groups will be spending hundreds of millions on the presidential race, it is at the Congressional level where big money can have the most impact. Many candidates, particularly in smaller states, cannot compete with independent groups, allowing individual wealthy donors to have an oversized influence on the future of the House or the Senate. Already, conservative interest groups have spent more than $17 million on televised attack ads in state and local races, and Jeremy Peters of The Times recently reported that they plan to spend more than $100 million by November. Total outside spending on Congressional races this year is likely to exceed the $300 million level of 2010. The conservative groups, like the Crossroads organizations founded by Karl Rove, have already moved aggressively against Democratic candidates in Nebraska, New Mexico, West Virginia and Wisconsin, among other states. The ads all spread the same misleading lines about health care reform and President Obama's record, to which Congressional Democrats are inevitably linked. "Fourteen thousand dollars," one Crossroads GPS ad intones, while a beleaguered father holds his head in his hands. Under President Obama and Senator Claire McCaskill, that's what every man, woman and child in America owes in new government debt. The ad wrongly suggests that individuals will "owe" the government a check for that amount, and of course never mentions that Mr. Rove's patron, President George W. Bush, was responsible for nearly five times more of the current debt than President Obama. Crossroads GPS claims to be a tax-exempt social welfare group, so it does not have to disclose its big corporate donors. That lie is no less outrageous than it was in 2010, when these groups first started sheltering their political activity under a tax loophole. It is long past time for the Internal Revenue Service to begin investigating and prosecuting this clear violation of the law. Congress could also require disclosure of donors, and end the coordination between outside groups and political parties. That is increasingly unlikely, however, as long as some members of Congress owe their elections, and their allegiance, to the same groups.