Mohamed ElBaradei at the World Economic Forum. (Salah Malkawi/GETTY IMAGES)

Mohamed ElBaradei, the 71-year-old Nobel Peace Prize winner, former head of the United Nations' nuclear agency and Egyptian opposition figure has just added a new line to his resume: He's been appointed the interim prime minister of Egypt. ElBaradei is in some ways a good choice: He's well-known, internationally respected, old enough that he's perhaps more likely to cede power willingly, and seen as too much of a statesman to indulge in the self-serving power grabs that have marked the tenures of past Egyptian leaders. And ElBaradei is likely to do well with international institutions such as the IMF, which now-deposed president Mohamed Morsi had rebuffed.

In other ways, though, the decision to appoint ElBaradei and his decision to accept the post are strange choices for Egypt at this moment. Here are a few.

(1) Little natural constituency, likely to alienate key groups

Egypt has more than a few serious problems right now, sadly, but one of the biggest is its political divisions, which are so wide and bitter that any single leader or group would struggle to govern. Maybe ElBaradei can unite the country, but he is not ideally situated for the task.

This is a moment when the Muslim Brotherhood and other Islamists, who are not few in Egypt, are probably asking themselves whether they should even bother participating in this government or just dedicate themselves to undoing it. ElBaradei is seen as associated with Egypt's relatively small population of well-off, well-educated, secular, liberal urbanites – or, worse, associated with Westerners. When I looked for a photo to illustrate this post, the first one that popped up showed ElBaradei smiling alongside Angelina Jolie, on stage at the Berlin International Film Festival.

ElBaradei is almost perfectly positioned to further enrage and alienate Islamists, who are popular among Egypt's many rural and low-income communities. While he had a warm relationship with the group before the revolution, making common cause with it against then-President Mubarak, he is so much the opposite of everything the Muslim Brotherhood stood for while Morsi was in power that the group could see him as anti-Brotherhood choice.

Shadi Hamid, who follows Egyptian politics for the Brookings Institution, told USA Today that ElBaradei and the Brotherhood are now "arch enemies of sorts." And it's not just Islamists. Hamid wrote on Twitter that ElBaradei "was the man pro-army nationalists seemed to hate most not too long ago."

(2) Has not proved to be a charismatic or populist leader

This also gets to the challenge of uniting Egypt, an urgent and difficult task for the country's post-Morsi government. ElBaradei, for all his considerable credibility, seems most comfortable giving interviews to reporters or posting to Twitter, not speaking before crowds.

On Jan. 30, 2011, as protests against Mubarak's government gained steam, ElBaradei landed at a still-idealist Tahrir Square. The protest movement was then the closest it would be to matching his vision; his name was already floating around as a possible leader for this leaderless movement. The crowds should have been putty in his hands. But his visit was strangely brief and disappointingly uninspiring, an opportunity lost for ElBaradei. It will only be more difficult now for him to champion the movement, and these are the people who should be his natural base.

(3) Compromising his democratic ideals

Even if the military coup that deposed Morsi and dissolved the constitution ends up being a good thing for Egypt's democracy in the long term, it's hard to think of anything more anti-democratic than a coup. ElBaradei, whatever his faults, has remained so untarnished in the two-and-a-half difficult years since Mubarak's fall in large part because of his adherence to the democratic idealism of those first revolutionary days. In January 2012, he quit Egypt's first post-Mubarak presidential race, announcing, "My conscience does not permit me to run for the presidency or any other official position unless it is within a democratic framework."

Yet, strangely enough, as the military stepped in to remove Morsi on July 3, ElBaradei was there on Egyptian state TV, implicitly blessing the anti-democratic act that has now installed him in power. Maybe, from ElBaradei's perspective, the coup was inevitable or necessary and that shouldn't force him to turn down the prime ministerial appointment just for the sake of consistency. But it's a sad bit of irony that, by taking the job, ElBaradei sacrifices some of the democratic credibility that got him there in the first place.