As the Bush administration scrambles to address the sudden decline of the country’s two largest mortgage finance companies, some of their longtime critics say the crisis has been building for years.

Among them is Jim Leach, a Republican former representative from Iowa, who began arguing two decades ago in Congress that the government-chartered mortgage companies, Fannie Mae and Freddie Mac, were unfairly insulated from the real world.

They were not subject to the same financial standards and tax burdens as their competitors, he warned, and if they ran into trouble, an implicit government guarantee to back them up meant taxpayers would be left with the losses.

“There are times in public policy making that one can feel like Don Quixote,” Mr. Leach said of his repeated legislative battles to rein in the two companies’ growth.