This BBC article speculates why the official re-election website of the Republican party is being blocked outside the US.

Mike Prettejohn, president of Netcraft, speculated that the blocking decision might have been taken to cut costs, and traffic, in the run-up to the election on 2 November.

He said the site may see no reason to distribute content to people who will not be voting next week.

Managing traffic could also be a good way to ensure that the site stays working in the closing days of the election campaign.

However, simply blocking non-US visitors also means that Americans overseas are barred too.

Netcraft monitors internet traffic patterns.
Whoever owns and manages the Bush-Cheney rel-election site can block whomever they want to, but why don’t they step forward and say why whole countries are blacked out? My ISP in Canada isn’t blocked.

BoingBoing readers say they can get in with a proxy.
Why would this site be blocked?

Update: A campaign spokesperson said it is for security reasons.