Indiana Gov. Mike Pence tried to firm up his endorsement of Texas Sen. Ted Cruz in an op-ed published Sunday in the Indianapolis Star. Gov. Pence endorsed Sen. Cruz on Friday, but only after he praised Donald Trump for his focus on jobs and other issues important to Hoosier State voters.

“In making my decision to support Ted, I am guided by the principles best espoused by former President Ronald Reagan,” the Republican governor wrote. “I am a Reagan Republican; drawn to his vision of less taxes, less government, traditional values and a strong military. Ted articulates that same agenda with an unwavering devotion to our Constitution, the sanctity of life, and the freedoms enshrined in the Bill of Rights.”

The Indiana Republican Primary is on Tuesday, May 3 and the latest polls–both public and private–show Mr. Trump ahead of Sen. Cruz by at least 15 points. Gov. Pence first endorsed Mr. Cruz on Friday, but it was a tepid endorsement that offered more praise for Mr. Trump than the senator.

“I particularly want to commend Donald Trump, who I think has given voice to the frustration of millions of working Americans with a lack of progress in Washington D.C.,” Pence said Friday on Greg Garrison’s radio program on WIBC.

However, on Sunday following the op-ed, Mr. Trump called Gov. Pence’s endorsement of Sen. Cruz “the weakest endorsement anyone has seen in a long time.”

“If you really take a look at Mike Pence, I think he gave me more of an endorsement than Ted Cruz,” Mr. Trump said on “Fox News Sunday.” “His donors and special interests obviously made him give an endorsement.”

“It’s over. I think it’s over now. Cruz cannot win,” Trump added. “I’m leading him by millions and millions of votes, and I’m leading him by 400 delegates. He cannot win.”