REUTERS/James Lawler Duggan
Ted Cruz, left, and Marco Rubio.
Rep. Trent Franks of Arizona wrote a letter addressed to Sens. Rubio and Cruz and sent it to fellow House Republicans to sign on Wednesday, Politico reported.
He said one of the two must drop out and join together with the other as the vice president on their ticket.
"For the sake of our country, the conservative cause, and future generations, we adjure you both to unite," he wrote.
Franks said his fellow Republicans welcome Trump to the "conservative fold" and are appreciative of Trump's criticism of President Barack Obama and his stance on illegal immigration, "among many other laudable qualities."
However, he added that "only time will tell" whether Trump remains as conservative as his campaign rhetoric.
"Accordingly, the stakes are too high to make his first public office President of the United States," he wrote.
In contrast, Franks said Cruz and Rubio both have "proven, full spectrum conservative records":
Through rivalry, disunity, and baseless hatred in our ranks, conservatives are now in danger of splintering our voice and ensuring that the Republican Party's nominee in the general election is Mr. Trump who is incontrovertibly, the weakest General Election candidate in the Republican field with the strongest probability of allowing Hillary Clinton to become President.
We believe there is another way. It may be the only way. We call upon all national security, free-market, and pro-family conservatives to boldly rally around the two of you together and ask you both to answer the call of statesmanship and decide between yourselves which shall be the candidate for President and which shall be the candidate for Vice President. However, if you fail, it appears a minority of our party will nominate a candidate for which the majority of our party has said they cannot vote.
There are fleeting moments in history when critical opportunities are clear enough for statesmen to see and still close enough for them to seize.
The laws of mathematics will not be repealed in this election cycle. The mathematics in this equation are clear to the reasoned mind: the two of you can unite and win together or remain apart and fail together.
Trump enters next week's swath of "Super Tuesday" races oming off of three consecutive wins in New Hampshire, South Carolina, and Nevada.
Contrary to Franks' argument, Trump insisted that he will continue to pick up voters as other candidates drop out. Trump tweeted on Wednesday that he'd pick up Cruz's voters with "no problem!"