There's a huge cottage industry of for-profit political and current-events "blogs" (really, magazines of small-form journalism) that have been coping with whatever these legal risks might be for ~10 years now. The Magazine is cool and all, but it's presumably dwarfed by Talking Points Memo, which has physical offices in multiple cities and full-time technical staff to back it up.
Political blogs/sites arguably have less legal exposure because they specifically deal with public figures and legally public figures have less protections (or at least a higher burden of proof) when it comes to things like libel.
That said, I can't really think of a plausible example of something The Magazine could hastily publish that could land them into legal trouble. I suppose a story full of falsehoods could tarnish its reputation, but I'm not sure it has a reputation to tarnish in the firs place.
TPM and other political blogs often cover national security, etc. Recent posts on that site indicate that they spend at least some time and money on legal counsel, but not necessarily for libel.
