This new Obama campaign ad, which is running in nine swing states, ties the offshoring charges to Mitt Romney’s offshore accounts:

Putting aside the substance of the debate over the true nature of Romney’s ties to Bain during the three years after 1999, which I talked about yesterday, it’s worth taking note of what the Obama campaign is trying to accomplish here. Obama and his advisers may well be perfectly happy for Romney to keep denying any direct managerial connection with Bain during the time period in question.

By continuing to hit Romney over offshoring during that disputed period, they hope to maneuver him into the position of continuing to deny responsibility for the activities of his firm during a time in which he was listed in documents as its CEO and chairman. That’s an argument that’s very hard for Romney to win, and dovetails with the broader case the Obama team is making about Romney’s character and unwillingness to be forthright or transparent about his finances.

That’s why the new ad ties the offshoring to the Swiss bank account and the “tax havens” in Bermuda and the Cayman Islands. “Doesn’t the buck stop with you?” is a far easier argument to grasp than the corporate jargon Romney has been forced to employ in rebutting it.