Ask HN: Political activism platform

After recently coming across news that representatives in my state have introduced problematic and comparatively faulty legislation in the upcoming session, I've been moved to start a bit of a grassroots effort locally to combat the passage of those bills.

I've seen quite a few sites that allow people to enter their zip code and find their representative, does anyone know how I can find, or has anyone written and open-sourced this kind of lookup implementation?

Failing that, are there any platforms that this community would recommend that would allow a simple landing page with copy text, facts and info with linked sources, and then a web form to find their representative? Perhaps even a WordPress plugin that I should look at and build on top of?

Ultimately I'm trying to avoid people leaving the page to perform the lookup since I can't guarantee that the receiving site will either handle incoming load, remain online, or even have the most up to date rep info. If someone's leaving the page, I'm hoping it's primarily to read linked sources from the "facts and info" section.

Thanks!