Facebook is resorting to old-school communication to make it harder for foreign agents to interfere with US elections. It will use postcard to send verification codes to would-be election ad-buyers.

To start off, the move will affect anyone who wants to place an ad that mentions a candidate in the 2018 mid-term elections by name. That could include candidates themselves, supporters, or those posting negative ads.

The ad buyer will need to provide a US mailing address. They’ll then get a postcard with a verification code that must be typed in before the ad can be bought.

There’s no pretence this will actually stop foreign agents placing ads, for example by hiring a US resident to receive and pass on the code. It’s simply an effort to make it a little more difficult (or, depending on your level of cynicsm, to show some effort has been made.) Facebook hasn’t said whether it will place restrictions such as not sending cards to PO boxes.

It’s certainly not the only ad related measure Facebook is taking. It’s running tests in Canada of new rules that mean paid ads of any kind must be linked to a Page. Clicking on that Page will show a full list of all the ads that Page is currently running, regardless of the target audience.

Meanwhile Facebook plans that election ads will include a link that shows who placed it, along with the criteria by which a particular viewer was included in the target audience. The site will also set up an archive of ads relating to federal elections that includes the cost, the number of views and a demographic breakdown of who saw it.