Chicago ? As Monday’s 30th anniversary of Watergate nears, student investigators at the University of Illinois have concluded that Deep Throat, the White House source who helped journalists unravel the greatest political scandal in American history, was most likely conservative commentator Pat Buchanan.

Since 1999, journalism professor William Gaines and his students have set about unmasking the elusive informant. Building on the work of their predecessors, this year’s class unanimously fingered Buchanan, a White House speechwriter during the Watergate era.

Buchanan may strike some as a surprising choice, because he was known as a Republican loyalist. But Tom Rybarczyk, one of the students, notes that at the time, Buchanan was miffed at Nixon for having recognized communist China.

The identity of the government official who slipped information to Carl Bernstein and Bob Woodward of the Washington Post has intrigued professional and amateur historians for three decades.