It’s becoming increasingly clear that Mitt Romney may soon have to make a difficult choice: Will he align himself with Marco Rubio, or with Kris Kobach?

Rubio has begun a full court press to sell his version of a GOP DREAM Act, releasing new details of it to the media yesterday. Rubio has now told reporters he hopes Romney adopts it. Romney himself was overheard the other day saying Republicans should consider supporting such a measure. A GOP DREAM Act would be central to Romney’s ability to pivot away from his hardline immigration stance during the primary and start making inroads among Latinos.

But in an interview with me, Romney immigration adviser and Kansas Secretary of State Kris Kobach — a widely respected voice on immigration among conservatives — laid down a set of conditions for Rubio’s DREAM Act that will be very difficult for the Florida Senator to meet. And this could present Romney with a hard choice.

Rubio’s proposal has not yet been released. But the Senator said yesterday that his bill would give non-immigrant visas to young illegal immigrants who were brought into the country by a certain date, provided they are high school graduates with no criminal record. That visa would enable them to work and go to school. In other words, they would be given legal status.

But Kobach — whose hardline ideas Romney adopted during the primary — tells me that the only way to make such an approach acceptable is for these illegal immigrants to be required to return to their home country before getting the non-immigrant visa.

“If the bill required the illegal alien to return to his country of origin and get in line for the non-immigrant visa, then that would not be amnesty, and that would be conceivable,” Kobach said. “If it’s extended to people who are here illegally, and they don’t have to leave the country, that would be amnesty.”

“Amnesty allows someone who is illegally in the country to remain but with lawful status — that gives the illegal alien what he has stolen,” Kobach continued, adding that he was nonetheless “encouraged” that Rubio is at least trying to come up with a solution that could be acceptable to opponents of “amnesty.”

This will be a very tough standard for Rubio to meet, if he is to offer any new policy that might hold even a little appeal to Latinos.

Kobach’s status with the Romney campaign is murky. While a Romney spokesperson recently said Kobach is merely a “supporter,” Kobach clarified the other day that the Romney campaign had privately confided to him that he remains an adviser to it on immigration policy.

But in a sense, Kobach’s exact status may be beside the point. His strict standard for a GOP DREAM Act he would be able to find acceptable signals that many right-wing immigration hardliners may oppose any GOP DREAM Act that constitutes anything meaningful in the way of a new policy, and that any effort by Romney to make inroads among Latinos by supporting such a policy could ignite a bitter intraparty battle