As the US celebrates the 250th anniversary of its founding, the country is guarding its door more tightly.

A new policy, poised to take effect soon, will fundamentally reshape how international students on F-1 visas and exchange scholars on J-1 visas are admitted into the US.

In mid-June, the Office of Management and Budget completed its review of a Department of Homeland Security proposal that would replace the current "Duration of Status" system with fixed admission periods for F-1 students and J-1 visitors.

The new policy is expected to be published in the Federal Register in short order and will become effective 60 days after it is published.

For almost half a century, with policy modifications finalized in the early 1990s, F-1 students and J-1 visitors could remain in the US with no fixed departure date for as long as they were enrolled in an academic program.