John McCainJohn Sidney McCainChuck Todd's 'MTP Daily' moves time slots, Nicolle Wallace expands to two hours Senate GOP divided over whether they'd fill Supreme Court vacancy  Asian American voters could make a difference in 2020 MORE praises American workers and denounces Wall Street in his latest TV ad, blaming "greed" among financial firms and stock traders for current U.S. economic conditions.

Since the collapse of investment bank Lehman Brothers and the sale of financial firm Merrill Lynch Monday, McCain has stumped for reforming Wall Street, alleging greed, waste, and corruption in the nation's financial systems.

That argument has become central to McCain's economic platform, and today's ad is his second this week to advocate for Wall Street reforms.