At multiple points during the planning calls for this campaign, we significantly changed our plans, the language, and our tact to make sure that our call was viewed as being considerate of international concerns. This letter originally had language to that effect, calling out GCHQ as a major part of the problem, and that surveillance does not only effect US citizens. For evidence of this, take a look at the "And Everyone Else Too" in one of the Facebook share graphics, which I added early this morning in response to concerns that that particular graphic was too US-centric.
When the banner goes live, we'll likely do IP-geolocation and offer users who are like outside the US a link to necessaryandproportionate.org, a petition to be delivered to international lawmakers.
However, given that many of the organizations behind the movement are US-based, it definitely still leans US-focussed. In some ways that's for the best: many of our organizations don't know how to be effective in changing laws in other countries. For example, during our planning it was suggested that we set up dial-in numbers for each country. After some research, we found that in many countries legislator's offices view calls as a nuisance and do not respond positively to them.
So, what I'm trying to say is: we're definitely trying to address this. And if privacy groups in other countries join us in setting up similar actions (as with the German rallies in solidarity with StopWatchingUs), we'll happily send international visitors their way.