The reeling housing market has come to this: To shore it up, two Senators are preparing to introduce a bipartisan bill Thursday that would give residence visas to foreigners who spend at least $500,000 to buy houses in the U.S.

The provision is part of a larger package of immigration measures, co-authored by Sens. Charles Schumer (D., N.Y.) and Mike Lee (R., Utah), designed to spur more foreign investment in the U.S.

Foreigners...