"We are about to go into general session to see if the whole platform committee will adopt them," Kansas Secretary of State Kris Kobach (R), who co-authored the law, texted The Hill when asked about a series of amendments the border hawk had proposed.

The outcome of the debate could be critical to whether the party can make inroads with Hispanic voters this fall, a key demographic group in a number of swing states. The party has made a concerted push to reach out to Latinos, giving a number of top Hispanic Republicans, including Sen. Marco RubioMarco Antonio RubioGOP senators plan to tune out impeachment week Republicans warn election results are 'wake-up call' for Trump Paul's demand to out whistleblower rankles GOP colleagues MORE (R-Fla.) and New Mexico Gov. Susana Martinez (R), speaking slots at the convention.

ADVERTISEMENT

A Republican source familiar with the platform committee's proceedings told The Hill that Kobach's proposals had been defeated by a subcommittee which dealt with immigration, and predicted they would not do well when presented to the full platform committee.

"Kris Kobach was on the subcommittee that dealt with immigration and didn't get any of his amendments in," said the source. "He presented eight amendments and none made it."

It was unclear exactly what the amendments required. Kobach was headed into the meeting and did not respond to a request for details.

Kobach was an early supporter of Mitt Romney during the primary, citing his immigration positions, and at one point advised Romney on immigration policy, though Romney's campaign denied that he was an official policy adviser to the campaign.

Romney ran hard to the right on immigration during the primary, but has sought since then to temper his rhetoric when talking about the emotional issue.