First, the reliance on Lee Smith's analysis in Slate is highly dubious. Smith is a poor source of expertise on the Arab world, and the reasons why have been explored elsewhere, notably on Abu Aardvark.
Secondly, and even more so than reliance on Smith, the author of the article gives credibility to the writings of Daniel Pipes, who is described as "a board member of the U.S. Institute of Peace, one of four members of the Presidium of the Jerusalem Summit, ostensibly a conservative organization that includes distinguished Israeli academics." Pipes is much more than this, he is a member and former head of the Middle East Forum, one of the most pro-Likudnik think tanks and pressure groups in the US. He has a long track record of Arab-bashing and foaming-at-the-mouth pro-Israel propaganda spouting. He is hardly an impartial informed commentator. The article also fails to mention that Pipes' appointment to the US Institute for Peace was extremely controversial and that in the end Bush had to take advantage of a congressional recess to pass it.
Thirdly, another source quoted is Stephen Schwartz (a frequent contributor to right-wing magazines such as the National Review, the Weekly Standard and FrontPage), who advocates not allowing Ramadan into the US and seems to think that the Beirut Daily Star, a relatively timid liberal English-language newspaper, is the mouthpiece of Arab nationalism. Take a look at the passage that was quoted from Schwartz's piece (on the generally right-wing TechCentralStation):
Even Hicham Chehab, news editor of the Beirut Daily Star, a newspaper obviously dedicated to Arab interests, was forced to admit early this month that "During the controversial visit to Britain last July by Sheikh Youssef al-Qaradawi, himself accused of sanctioning suicide bombers, Ramadan defended Qaradawi on the BBC television program 'Hard Talk.'"
This implies that a) even the Daily Star was forced to admit something negative about Ramadan, as if he's not controversial at all in the Arab world; b) Ramadan defending Qaradawi automatically makes him pro-suicide bombers; and c) doesn't even examine the controversy about what Qaradawi actually said (again Abu Aardvark has a lot on this.)
I am not a fan of Tariq Ramadan. I do think he is more dangerous than some people say he is, but not in the way that is usually thought of. Ramadan poses absolutely no danger to the US or to the students of Notre Dame University -- indeed, he would have been an asset, as he is an extremely intelligent and articulate Islamist thinker who can express his thoughts in other languages than Arabic with probably much greater ease than most Arab scholars. I also think that America is better than banning someone for what essentially is a "thought crime" -- after all the man hasn't done anything illegal or violent.
That being said, any real danger that Ramadan poses is with European Muslims. Taking France as an example, it is remarkable that the most prominent French Muslim institution, the Conseil du Culte Musulman, is dominated by Moroccans and Algerians but espouses a distinctly international form of Islamism akin to the thinking of the Egyptian Muslim Brotherhood. That's where Ramadan's influence comes in. The fact is that Arab immigrants to Europe who are religious have practically no choice but to turn to mosques dominated by thinkers and preachers whose ideas are the highly abstracted, intellectual kind of the Muslim Brotherhood rather than Islam as practiced by their parents and grandparents. This article [French] in the Moroccan weekly Le Journal has the details.
This does not mean that I link Ramadan with the violent, extremist trend in European Islam, but simply that he represents a kind of Muslim Brotherhood-type thinking that I absolutely reject. Furthermore, as a Moroccan I think it's a shame that religious Moroccan immigrants don't retain the "popular" Moroccan Islam (with its strong animist and Sufi influences) rather than adopt these ideas. But of course, that is their choice -- although it is limited by the dominance of a Ramadan-like discourse among European Muslim thinkers.
There are a lot of interesting comments below the Agonist article which take issue with some of these issues and others, it's worth reading them -- but it's a shame the author of the article chose to rely on the above sources. My own feeling in the "Is Tariq Ramadan a reformist or a fundamentalist?" debate is that he is both, and many people don't seem to get that this is not a contradiction.
P.S. I've just received an advanced review copy of a French book on Ramadan, called Tarek Raman devoilé (Tariq Ramadan Unveiled) which claims to be a five-year investigation into the man. From the blurb I suspect it's mostly negative, and I'll post a small review once I've had the chance to read it.