Sen. Barack Obama sharpened an economic attack on his Republican rival today, tying Sen. John McCain to the Bush administration’s lax treatment of foreign tax shelters. At an event in Indianapolis, Obama added several new populist paragraphs to his stump speech:

Sen. McCain thinks the economic policies of George W. Bush are just right for America… Just yesterday, Sen. McCain strongly defended the Bush policy of lavishing tax cuts on corporations that ship American jobs overseas. He made the peculiar argument that the best way to stop companies from shipping jobs overseas is to give more tax cuts to companies that ship jobs overseas. More tax cuts for job outsourcers. That’s what Sen.  McCain proposed as his answer to outsourcing. He said that’s – quote – “simple fundamental economics.”

Obama anchored his critique to that “fundamental economics” line:

Well, Indiana, my opponent may call that “fundamental economics,” but we know that’s just another name for the Wall-Street-first-Main-Street- last economic philosophy we’ve had for the past eight years – and that’s fundamentally wrong. If Sen. McCain wants to defend tax breaks for companies that ship jobs overseas, that’s his choice. But I say, let’s end tax cuts for companies that ship American jobs overseas, and give them to companies that create good jobs right here in Indiana — in the United States of America.

The Democratic nominee also got folksy while tweaking tax loopholes:

By the way, did you know that there’s a building in the Cayman Islands that supposedly houses 18,000 corporations. That’s either the biggest building or the biggest tax scam on record. And I think we know which one it is. That’s the system my opponent defends. That’s the system he wants to preserve. Well, Indiana, we’ve tried it John McCain’s way. We’ve tried it George Bush’s way. And we’re here today to say enough is enough. We can’t afford four more years of their “fundamental economics.” That’s why I’m running for president of the United States of America.

These passages aren’t that remarkable, but they are new at a time when Obama’s campaign has been marked by its strict discipline in repeating the same message, same speech and same ads.  Yet the “fundamental economics” talk, according to Obama’s aides, was just too good to pass up.