Politico reported Thursday that Cruz, a member of the Senate Judiciary Committee, has informed the White House and colleagues of his objection to U.S. District Court Judge Halil Suleyman Ozerden of Mississippi.
The New Orleans-based 5th Circuit hears cases from Texas, Louisiana and Mississippi.
“For a lifetime appointment on the court of appeals, I believe we should be looking for someone with a strong, demonstrated record as a constitutionalist," Cruz told Politico. "I have significant concerns that Judge Ozerden’s judicial record does not indicate that he meets that standard. For that reason, I do not believe he should be on the court of appeals, and I will oppose his nomination."
As a district court judge, Ozerden sided with the Obama administration in 2012 when he dismissed a challenge to the Affordable Care Act's mandate for contraception coverage by the Catholic Diocese of Biloxi, Miss. He ruled the administration was amending the policy, so it didn't need judicial review, according to The Washington Times.
The decision has given some Republicans pause. Ozerden lacks endorsements from conservative judicial groups, with Carrie Severino, chief counsel for the Judicial Crisis Network, saying last year that "we can do better than Judge Ozerden."
Kelly Shackelford, the president and CEO of the First Liberty Institute, told Fox News the group is "grateful" for Cruz's opposition.
“First Liberty Institute is grateful to Senator Cruz for his commitment to the Constitution and for his leadership in opposing Judge Sul Ozerden’s nomination to the Fifth Circuit. Elevating Judge Ozerden to a lifetime appointment on an influential federal appeals court would be a mistake," he said.
Ozerden has defended his judicial record amid the criticism.
“If you look at my record on the whole, you will see that I am committed to principles of textualism and following the law and following the Constitution,” Judge Ozerden said in response to criticism that he isn't conservative enough.
Liberal groups have also taken issue with Ozerden, accusing him of being hostile to workers' rights, the paper reported.
The Senate Judiciary Committee has held a hearing for his nomination but has yet to vote.
"I'm a yes)," said Senate Judiciary Chairman Lindsey Graham, R-S.C. He said Ozerden deserves a vote but was unsure if it would be a favorable one.
The judge's nomination is backed by Mississippi's two Republican senators, Cindy Hyde-Smith and Roger Wicker.
The White House and Sen. Majority Leader Mitch McConnell, R-Ky., declined to comment to Politico on the matter. More than 150 judges nominated to the bench by Trump since taking office have been confirmed.
He pushed back on accusations that he harbors racist beliefs and refused to answer questions about the legal advice he has given the White House on immigration policy.