A radical is someone who is willing to use extreme measures to achieve their political objectives. Nothing to do with the status quo. Totalitarian regimes, for example, usually maintain their status quo with radical zeal and measures.
The Quakers are political radicals. They are so extreme they utterly refuse to kill people, even when ordered.
edit - Given the article about it also on the front page, I thought I'd look it up in the original Mirriam Webster. The result is kind of interesting;
>2. (Politics)
>One who advocates radical changes in government or social institutions, especially such changes as are intended to level class inequalities; -- opposed to conservative. In politics they [the Independents] were, to use phrase of their own time. "Root-and-Branch men," or, to use the kindred phrase of our own, Radicals. Macaulay.
http://lexicon.x10host.com/?w=radical
And to contrast with my first port of call, in the Cambridge dictionary you get a politically neutral definition;
>believing or expressing the belief that there should be great or extreme social or political change