Are we morally obligated to become activists?

In the comments to Pied Cow’s post about the annoying condescension of “radical” anti-war pundits, High Arka writes:

The only honest answer for those of us on this side of the sword is that we’re guilty, rich cowards, playing the same terrible game as the others, only not winning as much treasure.

To which I responded:

This strikes me as an attempt at one-upsmanship on the moral purity scale. Were the pre-2003 residents of Iraq guilty of supporting Saddam’s evil regime? I’m sure George, Donald, and Dick thought so. I guess we’re all complicit on some level because we haven’t overthrown the government in Washington, but I don’t feel particularly guilty about the possibility that Obama might decide to send the drones after some guy on the kill list without asking for my opinion first.

Even though I disagree with Arka’s conclusion, I still think it raises a good question: Are Americans who don’t actively resist the US government (by not paying taxes, moving to another country, etc.) moral cowards who are complicit in its crimes?

Like I said, I tend to disagree with this, for two reasons (implied in the passage above): 1) Because we don’t pay taxes voluntarily and the government does what it does regardless of whether we consent, and 2) I don’t think the average American is morally obligated to pay for Dick Cheney’s crimes.