In two campaign stops Thursday, Mr. Obama invoked what he portrayed as a specific new example, citing a blog posting from a liberal advocacy group as he teed off on a longtime adversary, the U.S. Chamber of Commerce, over its political spending…

But a closer examination shows that there is little evidence that what the chamber does in collecting overseas dues is improper or even unusual, according to both liberal and conservative election-law lawyers and campaign finance documents.

In fact, the controversy over the Chamber of Commerce financing may say more about the Washington spin cycle — where an Internet blog posting can be quickly picked up by like-minded groups and become political fodder for the president himself — than it does about the vagaries of campaign finance…

The issue of the chamber’s funding first gained notice this week when ThinkProgress, a blog affiliated with the Center for American Progress, an influential liberal advocacy group, posted a lengthy piece with the headline “Exclusive: Foreign-Funded ‘U.S.’ Chamber of Commerce Running Partisan Attack Ads.”