Lawmakers in the Senate are poised to vote on a bill to reform oversight of Fannie Mae and Freddie Mac that would be much tougher on the government-sponsored enterprises than the one approved by a House committee in May. S.190, introduced last week by Sen. Richard Shelby, R-AL, would create a new regulator called the Federal Housing Enterprise Regulatory Agency for Fannie, Freddie, and the Federal Home Loan Banks. The proposal departs from a similar…