Required Student Lobbying and Tax Exempt Status of Universities

I have started reading about the impact of faculty telling students to write letters on behalf of candidates on the tax exempt status of the universities in which the professors teach. As I'm reading through a law book on section 501 c 3 it turns out that there have been revenue rulings on the subject of faculty telling students to campaign on behalf of a candidate. In Revenue Ruling 72-512 and 72-513 the IRS has held that a university is NOT participating in a political campaign by providing a political science course that requires the students' participation in political campaigns OF THEIR (the students') CHOICE nor by provision of faculty advisors and facilities for a campus newspaper that publishes the STUDENTS' editorial opinions on political matters. That contrasts with recent reports where the professor requires a given viewpoint. Also, an exempt broadcasting station that provides EQUAL air time to all electoral candidates in compliance with the Federal Communications Act does not violate the prescription against partisan political activities. (Bruce R. Hopkins, Tax Exempt Law of Organizations New York: John Wiley and Sons, 1983).

I am curious as to whether there have been subsequent revenue rulings about the kind of lobbying that has been reported in recent years (the book I have was published in '83). For example, there have been reports of professors requiring that students write letters on behalf of Kerry and of requiring that students take a required position regarding a law or proposed legislation.