Samantha Power, President Obama's nominee to be the next United Nations ambassador, stands in the Rose Garden at the White House on June 5. (Charles Dharapak/ASSOCIATED PRESS)

Samantha Power’s Senate confirmation hearing to be the U.S. ambassador to the United Nations begins Wednesday with a show of bipartisan support that contrasts sharply with the rancor that has marked the standoff over the use of the filibuster to block the appointment of several other presidential nominees.

Since President Obama nominated her last month to serve as his U.N. envoy, Power has received a vote of confidence from Israel’s ambassador to the United States and endorsements from several American Jewish leaders, some of whom had earlier seized on controversial statements she had made more than a decade ago about Israel. Power also received the public backing of a key Republican lawmaker, Sen. John McCain (Ariz.), who helped derail the secretary of state candidacy of the woman Power would succeed as ambassador, Susan E. Rice.

The Senate hearing provides a fresh opportunity for McCain and other Republican hawks to make their case for greater military support for Syrian rebels seeking the overthrow of President Bashar al-Assad. Before entering government, Power was an outspoken proponent of military intervention to prevent mass atrocities. But it remains unclear whether she has advocated the use of force in Syria, where more than 90,000 people are estimated to have been killed in the country’s bloody uprising and civil war.

The hearing could get heated on other subjects, as well. Sen. Marco Rubio (R-Fla.) plans to introduce a bill Wednesday that would seek to make U.S. funding to the United Nations’ regular budget voluntary, authorize the establishment of an inspector general position to audit the use of American contributions, and withhold U.S. funding to U.N. activities that are viewed as hostile to Israel, according to a Senate aide.

Still, the amicable prelude to this week’s hearing signaled a pause in Republican fire on the president’s national security team, which included attacks on Rice for a flawed public account of the deadly attack last year on the U.S. diplomatic outpost in Benghazi, Libya, and on former Republican senator Chuck Hagel for critical statements he made about the pro-Israel “Jewish lobby.” Rice, who withdrew from consideration as secretary of state, was appointed national security adviser. Hagel was confirmed as defense secretary.

It also showed that Power, a Pulitzer Prize-winning author and former Harvard scholar, has been successful in addressing concerns of lawmakers and conservative American Jewish leaders over her previous criticism of U.S. complicity in genocides and Israel’s human rights record.

“She aggressively reached out” to American Jewish leaders, said Abraham Foxman, executive director of the Anti-Defamation League, who offered an early endorsement of her nomination. Foxman said he and many other Jewish leaders are satisfied that Power, who oversaw U.N. affairs at the White House during Obama’s first term, has vigorously defended Israel at the United Nations. He cited her personal appeals to foreign governments to oppose the Palestinians’ effort to advance their statehood campaign at the United Nations.

The effort has helped blunt conservative critics, including Frank Gaffney, president and chief executive of the Center for Security Policy and a former acting assistant secretary of defense for international security policy, and 57 others, who urged senators to oppose her nomination. The critics, including retired U.S. congressman Allen West, retired intelligence official Lt. Gen. William “Jerry” Boykin, and Morton Klein, president of the Zionist Organization of America, have cited her public criticism of the United States and Israel’s human rights record.

The controversy over Power’s views on Israel dates to 2002, when she appeared on a public access television program in Berkeley, Calif. Power was asked what advice she would offer an American president in a hypothetical scenario in which one of the parties to the Israeli-Palestinian conflict were on the verge of committing genocide. She answered that a credible response would require the imposition of “a mammoth protection force — not of the old Srebrenica kind or of the Rwanda kind but a meaningful military presence.” “What we need is a willingness to actually put something on the line in the service of helping the situation,” she said. “And putting something on the line might mean alienating a domestic constituency of tremendous political and financial import,” she added, an obvious reference to the pro-Israel lobby in the United States.

Rabbi Shmuley Boteach, who once served as Michael Jackson’s spiritual adviser, had initially criticized Power for her “troubling” remarks that “maligned the American pro-Israel lobby.” But he said she has since reached out to him, offering personal assurances that she regrets her comments and that she is committed to Israel. Boteach, who will appear Wednesday at the confirmation hearing as Power’s guest, said that he found her explanations “sincere” and that he is “intent on transforming the Jewish community’s opinion of her.”