Looks like we need to define "radical".
Being a radical, in itself, is not always a bad thing. Some times radical reforms are necessary, like in times of war or extraordinary social upheaval. I don't consider Obama a radical, but I do consider some of his methods/decisions radical and necessary considering the economy. I think a radical approach required to get a handle on this economic mess is required and justified.
Who is or isn't a bad radical is often left to society to judge. The old verbage about one man's terrorists is another's freedom fighter sort of thing. Depends on what side of the fence your standing on.
Society, the majority, have not yet concluded that Obama is a "radical", anymore than Cheney is a "radical". Or a gun toting, tea bagging, ultra conservative, kill 'em all and sort 'em out later Texan might well be considered radical in many circles of society. No apologies to Texan's by the way, you know who you are.
Then there are those that rate far above mere "radical" status. McViegh comes to mind. Osma bin Laden as well. Anti abortionist murders, etc.