What is the fine-grained topic of the following text: Yet, behind the question is a increasingly important concern among U.S. educators: the pipeline of international students is shrinking dramatically as anti-immigration rhetoric and uncertainly over work visas has made the U.S. a less desirable place to earn a degree (see MBA Applications Take A Shocking Plunge At Leading U.S. Business Schools). Only return the topic.
Decline in international students in U.S. due to anti-immigration rhetoric and visa uncertainty