Deprived of a confirmation hearing on Susan E. Rice, congressional Republicans looking for a foreign policy fight may set their sights on Samantha Power, President Obama’s nominee to replace Rice as U.S. ambassador to the United Nations.

During a long and outspoken career as a journalist, author and human rights activist, Power, 42, has provided extensive fodder for questions about her views on many U.S. foreign policy issues and the United Nations itself.

In years past, she has written passionately about what she described as U.S. moral failings in Rwanda and the Balkans, criticized various administrations for refusing to “take risks” to prevent genocide and other atrocities, called U.N. Secretary General Ban Ki-moon “disappointing” and Hillary Rodham Clinton a ”monster,” and publicly pondered U.S. military intervention in the Israel-Palestinian dispute.

Power might have been foreshadowing herself when she wrote in a 2005 New Yorker commentary about President George W. Bush’s U.N. nominee John Bolton, an advocate of decidedly different politics. “The Senate Foreign Relations committee will have a lot to contemplate when the ever-quotable Bolton arrives for confirmation,” she wrote.

But while Bolton’s disdain for the United Nations was well known — he famously said it “wouldn’t make a bit of difference” if the top 10 floors of the U.N.’s New York headquarters were lopped off — Power is intimately familiar with the institution and has long defended its existence.

President Obama named Susan Rice to replace Tom Donilon as his national security adviser and Samantha Power to replace Rice at the United Nations in the Rose Garden Wednesday. (The Washington Post)

“There are few Americans, if any, who have spent as much time contemplating both the necessity of the United Nations but also its failures,” said Benjamin J. Rhodes, a colleague on Obama’s National Security Council staff.

As Obama’s adviser for multilateral affairs and human rights before resigning earlier this year, Power spearheaded initiatives on issues such as human trafficking and pushed for intervention to protect civilians in Libya, Rhodes said. Congress is likely to press her for her views on Syria, where the administration has debated whether to arm rebel groups.

Within the human rights and non-governmental community, the response was positive, despite some consternation over the past four years when she largely disappeared from public view and some questioned whether she had subsumed her human rights passion beneath bureaucracy.

Kenneth Roth, executive director of Human Rights Watch, said Power would be a powerful advocate at the United Nations. “She has seen evil at its worst,” he said, citing Power’s extensive writing about the Balkans, “and that has made her deeply committed to trying to prevent mass atrocities, which should be the top priority for the U.S. ambassador to the United Nations.”

Peter Yeo, executive director of the Better World Fund, said, “She knows the U.N. system inside and out, warts and all.”

Yeo said that Power may stand a decent chance of cultivating conservative support because democracy promotion and protecting civilians are priorities she shares with influential Republicans such as Sen. John McCain (Ariz.). McCain issued a statement calling Power “well-qualified” and expressed hope for her quick confirmation.

Max Boot, a conservative at the Council on Foreign Relations, called it a “good appointment” and expressed hope that Power would “call countries out on misconduct.” No one was “going to mistake her for a conservative Republican,” Boot said. “But I think there can be common ground between what she thinks and what some of us on the more conservative end of the spectrum think.”

Other conservatives, however, predicted a fight. Jeane Kirkpatrick is “turning in her grave right now,” Keith Urbahn, a former chief of staff to former defense secretary Donald Rumsfeld, tweeted in a reference to President Ronald Reagan’s U.N. ambassador. “I don’t know about you, but it might be helpful to have someone rep’ing America at UN who doesn’t think we are the source of world’s ills.”

Urbahn cited a lengthy article by Power in the March 2003 issue of the New Republic, the same month the United States invaded Iraq, in which she called for a “historical reckoning” with the darker chapters of America’s past — CIA-backed coups in Guatemala, Chile and Congo, and the doubling of U.S. assistance to Saddam Hussein the year he gassed Iraqi Kurds.

Conservative commentators Sean Hannity and Glenn Beck have listed Power, along with her husband, Cass Sunstein, a legal scholar who also worked in the Obama White House, among the most “dangerous” Obama appointees.

An Irish immigrant who came to this country with her parents at age 9, Power worked as a freelance journalist after graduating from Yale. During the 1990s, she covered the Balkan wars before returning to this country and earning a law degree from Harvard. She went on to win a Pulitzer Prize for her 2002 book, “A Problem from Hell: America and the Age of Genocide,” about U.S. and U.N. failure to stop the slaughter in Rwanda and Bosnia.

When then-Sen. Barack Obama read the book in 2005, he invited her for a talk and she ended up working in his Senate office for a year.

In 2007, amid writing numerous magazine articles and another book, “Chasing the Flame,” about Sergio de Mello, the U.N. representative killed in a 2003 Baghdad bombing, Power joined Obama’s presidential campaign as a foreign policy adviser.

Her entry into politics brought new attention to her previous writing and public statements, including a 2002 television interview in which she called for investing billions of dollars “not in servicing Israel’s military, but actually investing in the new state of Palestine,” and said the “imposition of a solution” there would require “external intervention.”

Asked what she would advise a U.S. president, Power said that “what we need is a willingness to put something on the line” that might mean “alienating a domestic constituency of tremendous political and financial import.”

After some accused her of being anti-Israel, Power said even she found her youthful comments “weird” and indecipherable.

Shortly after calling Clinton a “monster” who was “stooping to anything” to win the Democratic presidential primary in 2008, Power apologized and resigned from Obama’s campaign team. When he became president, however, she joined the National Security Council staff.

Lynch reported from the United Nations.