Brian Brown is calling on Republican leaders in the Senate to do “whatever it takes” to confirm Neil Gorsuch, President Donald Trump's pick for the Supreme Court.

Brown, who heads two groups opposed to LGBT rights, the National Organization for Marriage (NOM) and the International Organization for the Family, said in an email sent Monday that confirming Gorsuch is the first step in NOM's plan to reverse the high court's groundbreaking 2015 finding in Obergefell that gay and lesbian couples have a constitutional right to marry.

“As you know, the path to reversing the illegitimate, anti-constitutional ruling of the Supreme Court redefining marriage begins with the confirmation of Judge Gorsuch,” Brown wrote. “Once he becomes a justice, we will likely be only one vote shy of reversing this horrible decision.”

NOM is prompting a petition that urges Senate Majority Leader Mitch McConnell to support a change in the Senate rules that would require a simple majority to confirm Supreme Court justices – the so-called nuclear option.

During his Senate confirmation hearing, Gorsuch said that Obergefell was settled law, though he did not reveal his personal views on marriage equality.

“Is absolutely settled law. There's ongoing litigation about its impact and its application right now, and I cannot share my personal views without suggesting mistakenly ...” Gorsuch said before being interrupted.

Christian conservatives, however, are convinced that Gorsuch would vote to overturn Obergefell and Roe, the 1973 landmark decision on the issue of abortion.

“Judge Gorsuch’s record shows that he is committed to stopping judicial activism and interpreting cases on the basis of what the constitution actually says rather than on the basis of an ideological bias or of a desire to legislate from the bench,” Brown wrote. “Such judicial activism has been evident in many decisions of the last several decades, including notably the fateful Roe v. Wade decision on abortion in 1973 and the much more recent Obergefell decision that sought to supplant a radical redefinition of marriage for what marriage intrinsically is: the union of one man and one woman. Like Justice Scalia whom he will replace, Judge Gorsuch surely sees the errors of these decisions and, if given the opportunity, will rule to overturn them and put our country back on the right track of respecting life and marriage.”