Reid Not Backing Down on Romney Tax Claims

But still won't reveal source. Romney says he's paid what law required.

Senate Majority Leader Harry Reid is not backing down from his second-hand allegations that Mitt Romney did not pay taxes for 10 years, but he still won't name his sources for the unproven claim.

Reid said earlier this week that an investor in Romney's former private equity firm told him the Republican presidential candidate paid no taxes for a decade.