From my admittedly poor understanding of the legal challenges, Obama has stated he doesn't need Congressional approval under the War Powers Act (which means Congress needs to approve the troop presence after 90 days or the troops must withdraw) because it is a NATO operation. In my non-legal mind, the last time I checked, the US basically is NATO as far as military presence.
I think it's absolutely disgusting that the Obama administration is circumventing the process for getting approval of continued military action. By bypassing Congress, they're essentially saying the representatives of the people aren't worth listening to. For anybody who considers themselves anti-war, they should keep Obama's pro-war ideology in mind when casting their ballot in 2012.
You can view the Obama administration's side of the argument here. Not surprising, one of the chief defenders of Obama's war in Libya was a harsh critic of President George W. Bush on similar policies.
And on another note, Shepard Smith wants to know what happened to all the anti-war liberals.