Zeke Miller says Mitt is running out of donors because he overwhelmingly relies on the support of the very wealthy:
Romney has proved unable to tap into the emotion-drived small-dollar contributions that helped power Barack Obama in 2008, and which fueled even his more Establishment rival, Hillary Clinton, this time four years ago when she too began to run out of big donors. The result: Republican fundraisers say that despite his success so far, they think Romney is fast approaching a wall, and that he will likely be forced to pay for the campaign out of his own deep pockets.
The Dish 