Senator Elizabeth Warren, the champion of Main Street versus Wall Street, just got another boost to the presidential campaign she said she isn't running. It lies in the $13 billion deal that JP Morgan Chase reached with the US Justice Department. The settlement, which ends the government's probe into the bank's risky mortgage business, reportedly represents the largest amount a single company has ever committed to pay Uncle Sam. That's significant - but so is the bank's unusual admission that it failed to disclose the risks of buying its mortgage securities. Warren was a force in both aspects of JP Morgan's day of reckoning. After the economic collapse of 2008 - and before her election as senator - Warren led the charge for Wall Street accountability while overseeing the government response to the banking crisis. As senator from Massachusetts, she ... isn't shy about acknowledging her role in achieving them. In September, Warren [said] that her lobbying of Mary Jo White, the newly installed chairwoman of the Securities and Exchange Commission, played a key role in getting government regulators to require more companies to admit wrongdoing, not just pay fines - which is what happened in JP Morgan's case. The JP Morgan headlines play out as the stock market surges and unemployment ticks up. The gap between America's rich and poor is growing bigger. The divide creates an opening for a Democrat who speaks to the shrinking middle class, as well as to those already squeezed out of it. Warren could be that candidate, if she chooses.