President Trump's nominee to replace Brett Kavanaugh on the influential D.C. Circuit Court of Appeals, Neomi Rao, secured Senate confirmation on Wednesday -- and she did it with the support of a key Republican who had questioned whether she supported the expansive "substantive due process" judicial theory that has been used to justify pro-abortion laws.

Rao, 45, the so-called Trump "regulatory czar" who pushed for deregulation as head of the White House Office of Information and Regulatory Affairs, was confirmed on a straight party-line vote, 53-46. No Republican opposed Rao, and no Democrat supported her.

Rao also worked in the George W. Bush White House but has never tried a case in state or federal court.

Her confirmation process hit heavy turbulence late last month, when Missouri Republican Sen. Josh Hawley told Axios that he had "heard directly from at least one individual who said Rao personally told them she was pro-choice." Hawley clarified, "I don't know whether that’s accurate, but this is why we are doing our due diligence."

“Josh Hawley is single-minded and focused only on representing the common-sense conservative voters of Missouri. No threat from any group in Washington on either side of the aisle matters to him.” Hawley spokeswoman Kelli Ford told Fox News in a statement at the time, as multiple conservative groups immediately rushed to Rao's defense.

According to Hawley, Rao's academic writings have indicated she may support the concept of "substantive due process," a legal framework that identifies constitutional rights not expressly provided by the text of the Constitution. Conservatives have opposed the use of substantive due process to provide for some rights, including the rights to privacy and abortion, which are not stated in the constitutional text but are seen as implied.

For example, in a 2011 Notre Dame Law Review article, Rao referred to the "anti-abortion movement," rather than the pro-life movement. Rao, describing other courts' reasoning and not necessarily her own, also discussed the principles that liberals say justify a constitutional right to abortion.

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“Constitutional courts frequently suggest that dignity requires the right to a certain degree of individual autonomy, a space for freedom of action without interference by the state," Rao wrote. "These decisions suggest that providing a wide sphere of autonomy and ensuring a minimum of state interference with property, bodily integrity, and privacy enhances intrinsic dignity.”

Rao went on to call for more legal clarity on the topic: “In the existing confusion, it may be desirable for liberty (not to mention clarity) to take dignity talk out of our constitutional law. But if, as I suspect, dignity cannot be extricated, in partbecause of the established pull of the word, then we need clarity about what dignity means."

In a reference to substantive due process, Hawley has said that "the implied fundamental rights cases are where the courts just make stuff up," and that he will press "every" judicial nominee on the issue.

Many conservative groups spent big on ads to change Hawley's mind. Columnist Quin Hillyer, meanwhile, wrote in The Washington Examiner that Hawley's approach was a "dicey" push for a judicial litmus test.

"Conservatives have argued long and correctly that professional qualifications and personal integrity, along with a basic commitment to the Constitution itself, should be the only determinants of nominees’ fitness for appointment to federal judgeships," Hillyer wrote. "In particular, conservatives have inveighed against any result-oriented, single-issue litmus tests for judges, especially for those below the level of the Supreme Court."

Lawmakers from both parties had additionally expressed concerns about her past writings on the topics of date rape and other sexual assault. As a Yale undergraduate Rao suggested that intoxicated women were partly responsible for date rape. She also criticized affirmative action and questioned equal rights for women and gay people.

Rao distanced herself from language she used as a college student, saying at her confirmation hearing that she cringes at some of the language she used in opinion articles she said were intended to be provocative.

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Sen. Joni Ernst, R-Iowa, who recently revealed she was raped in college, called Rao's 1990's opinion pieces "absolutely abhorrent and reprehensible at best," but said she was reassured after Rao wrote a letter to senators repudiating her past views.

Ernst and other Republicans said she was qualified despite her lack of courtroom experience. They said Rao's work on federal regulations qualifies her for the District of Columbia circuit, which handles many administrative appeals of executive branch actions, Ernst said. But she and other Republicans said they might view Rao differently if she is nominated to the Supreme Court.

Rao, widely seen as a future candidate for a Supreme Court seat, is a member of the conservative Federalist Society. The legal policy group has played a key role in Trump's judicial nominations, including Kavanaugh's elevation to the high court.

Democrats staunchly opposed Rao, citing her lack of trial experience and publicly stated pride at rolling back federal rules on Trump's behalf. Rao said at her confirmation hearing that she and Trump have successfully pushed deregulation that "gets government out of the way" and helps small businesses and other companies create jobs.

Senate Judiciary Committee Chairman Lindsey Graham, R-S.C., called Rao "an outstanding choice" to serve on the District of Columbia Circuit, widely considered the nation's second-most-important federal court, below only the Supreme Court.

"She is an expert on administrative law and has a sound, conservative judicial philosophy that one would expect from a Republican nominee for such an important position," Graham said of Rao.

But California Sen. Dianne Feinstein, the panel's top Democrat, said Rao has a "troubling and aggressive record" on deregulation, particularly on rules that protect health and the environment. She was especially troubled at Rao's efforts to dismantle a rule to increase fuel economy standards for cars, Feinstein said. The rule is based on a law Feinstein co-wrote.

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The Democratic National Committee said in a statement that Rao does not belong on the federal bench.

"A vote for Neomi Rao is a vote for a judge who blamed survivors of sexual assaults for being attacked. It is a vote for a judge who claimed sexual orientation is a 'behavior' that can be changed," Elizabeth Renda, the Democratic National Committee's women's media director, and Lucas Acosta, the committee's LGBTQ media director, said in a joint statement.

The Republican senators who voted in favor Rao "willfully turned their back on women, the LGBTQ community, people with disabilities, low-income families and countless others," the DNC said.

The Associated Press contributed to this report.