The results of congressional generic-ballot polling aren’t the only sign that Democrats might make gains this November. Other indirect measures portend a partisan shift, too, the latest being reflected in college commencement speakers.

Regular readers of this column may recall that a year ago I wrote about the paucity of conservative speakers at college commencements. Most notably, I exposed that Bill Cosby, a commencement fixture for more than a decade, was left off the invitation list last year after his comments about hip-hop culture and other delicate topics forced liberals to turn against freedom of speech. Cosby’s on the outs again this year, too. But that’s no surprise.

What’s revealing is that liberals are pressing their advantage. While it’s not particularly surprising that Democrats and liberals dominate the commencement-day platform, it is notable when the trend worsens. And that’s what has happened in 2006. Republicans and conservatives were in decline on campuses this spring.

In 2005, I conducted my analysis in May, just before the list of speakers was complete. To get the most complete final numbers this year, I waited until now.

Last year, I pointed out that among commencement speakers with political credentials, Democrats and liberals dominated. A critical factor in this was the frequent selection of former Clinton administration appointees, from Janet Reno to Joycelyn Elders. Surprisingly, of the 50 incumbent members of Congress addressing graduates last spring, a narrow majority, 28, were Republicans. But as I mentioned then, the institutions that chose Republicans were generally less prestigious.

This year, the number of congressional speakers rose significantly and the partisan results reversed. Speeches by congressmen rose by 30 percent to 65. The number of GOP addresses declined by two, to 26, while Democratic addresses jumped dramatically, from 22 to 39.

Among other elected officials (governors, state legislators, mayors, etc.), the Democrats almost perfectly maintained their partisan advantage. In 2005, there were 39 speeches by other elected officials, of which Democrats delivered 62 percent. In 2006, there were 29 other speeches and Democrats gave 59 percent.

The key trend, though, is that there were fewer GOP congressional speakers and more congressional Democrats. Does this mean congressional Republicans are being shunned more than ever? Or does it mean House and Senate Democrats are perceived to be on the rise and more worthy of invitations? Perhaps it simply illustrates how out-of-touch academia is with mainstream America? Only time will tell.

The commencement-speaker list also provides insight on the 2008 presidential race. For example, Sen. John McCain (R-Ariz.) spoke at Jerry Falwell’s Liberty University, a telling shift from his 2005 address to graduates of the Maine Maritime Academy. Senate Majority Leader Bill Frist (R-Tenn.) felt compelled to shore up his base with a speech before University of Tennessee grads, while Massachusetts Gov. Mitt Romney did strategically targeted outreach by speaking to the graduates of Coe College in Iowa. After making three major addresses in 2005, former New York Mayor Rudy Giuliani (R) gave only one speech in 2006, to a smaller law school. Are his presidential fortunes in decline?

On the Democratic side, front-runner Sen. Hillary Clinton (N.Y.) delivered three speeches, though none at academically notable institutions. It seems as if she was angling for Everywoman status with her oratory at Buffalo State and Long Island University. Former Sen. John Edwards (N.C.) wangled an invite to the University of Maine, targeting an early caucus state. Sen. Evan Bayh (Ind.) had only home-state cooking at DePauw, as did Iowa Gov. Tom Vilsack at Grinnell College.

Hill is director of Hill Research Consultants, a Texas-based firm that has polled for GOP candidates and causes since 1988.