One of the arguments anti-immigration reform senators like Ted Cruz (R-Tex.) have used is that Republicans can win Hispanic votes without supporting immigration reform. Cruz has claimed to have won “over 40 percent of the Hispanic vote” in 2012.

Sen. Marco Rubio Sen. Marco Rubio (R-Fla.) (Joe Raedle/Getty Images)

Unfortunately, there is no public polling that supports such an assertion. There were no exit polls done in Texas but other election data and outside polling groups show he won 34 to 36 percent of the Hispanic vote. Cruz’s spokewoman told me Wednesday evening, “The 40 percent claim is from an internal poll conducted after his election victory.” They have offered to make this pollster available, and I will certainly report back on how he reached a conclusion no independent pollster or analyst did.

It is also noteworthy that Cruz had worked on behalf of the staunchly pro-immigration reform George W. Bush (in his campaign and his administration), so voters might well have assumed he still held pro-immigration views.

It is instructive to compare his performance to Sen. Marco Rubio (R-Fla.), who ran in 2010 on his immigrant story and has long been a proponent of increasing legal immigration. Rubio in his first race (heavily supported by pro-immigration reform former Gov. Jeb Bush) got 55 percent of the Hispanic vote, higher than his overall percentage (49 percent) of the vote in a three-way contest.

Sen. John Cornyn (R-Tex.), up for re-election in 2014, will be an interesting test case. Last time he got 36 percent of the Hispanic vote according to exit polling in 2008. If he remains opposed to the only passable version of immigration reform, will he do worse or better with Hispanics? If you think his anti-Gang of Eight vote won’t hurt him with Hispanics, I’ve got a bridge to sell you. Likewise, will Cruz do as well with Hispanics in Texas in 2018 as he did the first time (whatever the correct percentage was), now that he has lambasted immigration reform and its supporters? That, I would suggest, is fanciful.

This is the nub of the dilemma for Republicans. If you are anti-immigration reform in a deep-red state, you may do poorly with Hispanics but still win. (And you’ll get lots of attention from anti-immigration reform think tanks, talk show hosts and pundits.) The attention is irresistible and won’t cost a Republican his seat in most circumstances. Outside of safe red states, however, the GOP’s huge deficit with Hispanic voters (as well as Asians) creates a steep if not impossible climb to victory.

Rep. Paul Ryan (R-Wis.) is a longtime supporter of immigration reform who plainly believes in the economic benefits of enhanced immigration:

Should Ryan run in 2016, his support for immigration reform will distance him from Romney’s position during the campaign that illegal immigrants ought to “self-deport.”

Pressure on Republicans from shifting demographics are evident in Ryan’s own Wisconsin district, which has the second largest Latino population among the state’s districts.

But Ryan is not a new convert to immigration reform and he says politics are not driving his embrace of it. His work on it goes back to his days as an aide to Jack Kemp, the late congressman who saw immigration as part of a free-trade agenda. . . .

If Ryan is worried about a conservative backlash on immigration, he is showing no signs of it.

He has offered to debate anyone who says an “earned” path to citizenship is the equivalent of amnesty.

Those Republicans who take issue with Rubio, Ryan and others on immigration face a moral and practical dilemma: Can a party that cannot win substantial votes from nonwhite voters survive and claim legitimacy in a multiethnic, increasingly diverse country?