By Christina B. Farnsworth. Add to the list of unintended consequences of changing the immigration rules, the length of time foreigners can visit the United States. Potential new immigration rules could severely restrict the length of visas and, in many cases, the amount of time visitors can live in their U.S. vacation homes. And that worries the National Association of Realtors (NAR), which opposes the proposal.

If the new rules are approved, visitors will have to state the purpose and length of their visits with more precision than in the past. If the "appropriate" amount of time needed to accomplish the purpose of their visit can't be determined, visitors would only be granted maximum 30-day visas rather than the six months standard now. The NAR thinks such rules would hurt vacation home sales.