Republicans would be well advised to take a break from Benghazi and ponder their long-term status on the home front. A new U.S. Census report, having crunched the electoral numbers, warns that the future does not look grand for a diversity-challenged party that owes its very existence to white people.

The Census statisticians announced Wednesday that the 2012 presidential election was an historic watershed; for the first time, whites voted at a lower rate than black voters - 64.1 percent of eligible whites, 66.2 percent of eligible blacks. This happened partly because roughly two million whites who voted in 2008 opted to stay home in 2012, and partly because blacks (particularly black women) upped their participation.

Care to guess why black turnout spiked? It's party because blacks were ticked off at the GOP's vote suppression strategy. The party's varied attempts to keep blacks from voting in battleground states wound up backfiring. The Census report didn't make that specific connection, but the stats tell the story. Turnout jumped in key states like Ohio and Florida, where Republicans officials narrowed the early voting hours - a move that prompted even more blacks to show up and weather the long lines, to ensure that their votes would be cast.

Republicans might be tempted to argue that the last two elections were outliers, given the fact that a black guy headed the Democratic ticket. But the Census report looks at the big picture, and therein lies the GOP's abiding problem. Since 1996, the white share of the electorate has dropped by nine percentage points. The black share has risen by three points.

And, perhaps most importantly, the Hispanic share has risen by four points since 1996 (with the potential to go far higher, if the much-vaunted "sleeping electoral giant" ever fully awakens). Only 48 percent of eligible Hispanics voted in 2012 - far lower than the white and black participation rates - but their burgeoning population gives them a larger electoral share. Because of Hispanics, Republicans in the last two presidential elections lost states that were once GOP bastions - Virginia, Colorado, Nevada, Florida. A growing Hispanic electoral share is irreversible.

The sane wing of the GOP already knows what the Census just confirmed - that the party is way too dependent on white voters (who are losing, and will continue to lose, electoral share); and that, going forward, the party is potentially at the mercy of minority voters (who are gaining share, and who generally detest Republicans).

"Biological differences"

Clearly the white party needs to become more diverse. The problem is, it doesn't have a clue how to do it. Just check out what happened this week on the immigration reform issue.

It's bad enough that Republicans are fighting among themselves on how or whether to craft a path to citizenship for undocumented immigrants - as evidenced, for instance, by the conservative National Review's cover story, which eviscerated GOP Senator Marco Rubio for working so assidulously on his reform bill (cover headline: "Rubio's Folly"; editorial headline: "Rubio's Amnesty"). Worse yet (or, from the Democrats' perspective, better yet), a prominent conservative think tank, the Heritage Foundation, has arguably turned back the clock on GOP minority outreach by roughly 100 years.

Maybe that's too strong. Suffice it to say that Jim DeMint's policy shop has turned back the clock by reviving white-supremacist racial theories that date back 100 years.

As you may know already, it's been quite the sorry spectacle. For starters, Heritage - which helped kill immigration reform six years ago (thus souring Hispanic voters even further on the GOP), and which is now helmed by ex-GOP senator DeMint - put out a report claiming that a reform law would taxpayers trillions of bucks. Rubio and other pro-reform Republicans said the report was tantamount to junk science, because it omitted all the economic benefits of bringing those immigrants into the economy.

But the real fun commenced when one of the report's co-authors, Jason Richwine, was outed as a practitioner of crackpot racial theories. To wit, from his doctoral dissertation: "The average IQ of immigrants in the United States is substantially lower than that of the white native population, and the difference is likely to persist over several generations....No one knows whether Hispanics will ever reach IQ parity with whites, but the prediction that new Hispanic immigrants will have low-IQ children and grandchildren is difficult to argue against."

His message in a nutshell: Whites inherently smart, minorities inherently stupid. As he himself wrote in a 2009 book review, "Biological differences cannot be wished away."

Way to go, Heritage - which late this week has been busy trying to distance itself from the same guy that it hired to be a Senior Policy Analyst in Empirical Studies. (A flak for DeMint said that Richwine's doctoral dissertation is "not a work product of the Heritage Foundation." Fine. But didn't Heritage check his credentials before it brought him aboard to work on immigration reform?)

Conservatives who understand the need to woo Hispanics have gone ballistic. Jennifer Korn, who runs the conservative (and pro-reform) Hispanic Leadership Network, said yesterday: "Richwine’s comments are bigoted and ignorant. America is a nation of immigrants; to impugn the intelligence of immigrants is to offend each and every American and the foundation of our country."

Hispanics are surely offended. And if the white party continues to offend vrtually every voter who isn't white, the next Census electoral roundup is sure to be even grimmer.

-------

Follow me on Twitter, @dickpolman1