The latest criticism from the Trump administration of Harvard University highlighted the number of international students entering the United States each year for higher education.

The Administration’s move is the latest escalation in its attack on elite universities across the U.S., with heavy penalties levied on Harvard, including a threat to revoke the university’s tax-exempt status. Those penalties have only grown more severe as Harvard has refused to capitulate to the Administration’s demands.

The Trump administration is relying on an obscure bureaucratic lever to stop the school, the latest in a series of aggressive moves.