WASHINGTON — The nomination of Samantha Power for America’s UN envoy garnered significant support Thursday, and not just from Obama backers.

Power’s nomination, announced Wednesday in a White House Rose Garden ceremony, may face a rocky confirmation process. As Foreign Policy’s The Cable blog noted, any case against Power would enjoy an “extended paper trail” owing to her “decades-long career as a journalist and Harvard scholar dedicated to human rights abuses and genocide.”

A sign of the partisan divide that may slow the nomination came from the main Democratic and Republican Jewish outreach groups. While the National Jewish Democratic Council expressed “full confidence” that Power would continue the US support for Israel at the UN, the Republican Jewish Coalition was more critical.

“Samantha Power has a record of statements that are very troubling to Americans who support Israel,” RJC executive director Matt Brooks said after the nomination was announced.

An early taste of how the nomination’s opponents may wield that record came later Wednesday in a statement by the right-wing Zionist Organization of America.

“The overwhelming evidence of her entire record causes us great fear and concern as to her appropriateness for this post,” the ZOA said in a comment that included a list of her past controversial statements. “The ZOA, in opposing her nomination, cited Power’s documented record of outspoken anti-Israel statements and lack of diplomatic tact and has urged the Senate to vote her down when her nomination comes before it,” the group said.

But the complaints from RJC and ZOA were dwarfed by a series of high-profile endorsements from conservatives and well-known pro-Israel figures, endorsements that will likely serve as ammunition for Power’s backers in Senate confirmation hearings.

Former Connecticut senator Joe Lieberman offered what is — for him — high praise for Power in a conversation with Foreign Policy. “Generally speaking from her writings, Samantha is probably more personally interventionist as a matter of American foreign policy based on human rights than this [Obama] administration has been. I’m very encouraged by the president’s appointment.”

Influential Republican John McCain, the party’s 2008 presidential candidate, concurred. “I support President Obama’s nomination of Samantha Power to become the next US ambassador to the United Nations. I believe she is well qualified for this important position and hope the Senate will move forward on her nomination as soon as possible,” McCain said in a statement.

Harvard law professor Alan Dershowitz, a noted advocate for Israel who authored the book The Case for Israel, praised Power as a human rights expert “perfectly suited to stand up to the United Nations’ notorious double standard and inversion of human rights.

“To be sure, Samantha has said some things she now regrets,” Dershowitz added, “about Hillary Clinton, about Israel and about other controversial matters.”

But her work during the first Obama term as senior director for multilateral affairs and human rights at the National Security Council offered her many opportunities to support Israel — opportunities she took, according to Dershowitz. “While serving in the Obama administration, she has supported Israel’s security and defensive actions against terrorism,” he argued. “She stands squarely behind President Obama’s pledge never to allow Iran to acquire nuclear weapons, even if preventive military action is required. She played a pivotal role in persuading the United States and some of our European allies to boycott the notorious Durban II conference, sponsored by the United Nations Human Rights Council in Geneva, which invited Ahmadinejad to be its keynote speaker.”

The Anti-Defamation League, a major pro-Israel group, was among the first to endorse Power’s appointment, offering similar praise for Power’s efforts in opposing the demonization of Israel in international bodies.

“As head of President Obama’s multilateral affairs efforts, Samantha engaged in an all-hands-on-deck US campaign against Palestinian unilateral efforts in the UN to circumvent peace negotiations,” the ADL’s director Abe Foxman and chair Barry Curtiss-Lusher said just hours after she was nominated. “She experienced first-hand the hostility faced by Israel and the abuse of the UN bodies to promote anti-Israel bias. As someone who appreciates, to the core of her being, the meaning of international human rights mechanisms, Samantha is clear eyed and understands the injustice of their abuse to target Israel’s legitimacy.”

Shmuley Boteach, an unsuccessful Republican candidate for Congress in 2012, called Obama’s nomination of Power “one of the most impressive actions of his presidency,” and said that those who claimed she possessed anti-Israel animus “are wrong.”

“As the author of the 2002 Pulitzer-prize winning best seller, A Problem from Hell, Samantha has emerged as the world’s foremost agitator against genocide and, as a member of a nation who experienced the worst mass slaughter of any in history, I have always been in awe of a woman who has given voice to God’s ancient plea to humanity, ‘the blood of your brother cries out from the earth,’ ” Boteach wrote in The Times of Israel.