A proposal by Democrats for a government-sponsored enterprise subsidy for affordable housing has stalled GSE reform in the House and is threatening to become a volatile issue when the U.S. Senate begins to consider its own GSE bill next month. A provision in H.R. 1461 requiring Fannie Mae and Freddie Mac to set aside 5 percent of their after-tax earnings for affordable housing activities not only has sparked partisan fights in the House but among…