In almost 19 months, the capital cushions at Fannie Mae and Freddie Mac will fall to zero, which means if either government-sponsored enterprise (or both) suffers a net loss in a quarter, Uncle Sam will need to step in and supply cash to get the afflicted party back to zero. Depending on whom you talk to in the mortgage industry, a capital draw from Treasury could set off irrational behavior on the part of Congress or it’s much ado about nothing. …