The Facebook Page maintained by the Department of State includes on its fan pages links to two political pages: Barack Obama’s page, maintained by the Democratic National Committee, and Joe Biden’s page, set up by his now defunct political committee.
You can access these pages through, say, the Department’s page for the Kabul embassy. It is the 21st century equivalent of putting up ‘Obama for America’ yard-signs on the lawn of a U.S. embassy. Now — this is a tiny and inconsequential violation of the rules, but it does seem to break the Hatch Act, which prohibits government from promoting political entities.
A link to Obama’s White House would be acceptable. The State Department is still figuring out its best practices when it comes to social media, but there are some bright lines, and this is one of them. National security resources, in particular, cannot be used in any way for political purposes, even inadvertently, as is the case here. Clarifying what’s permissible and what isn’t is important across the government, but State plays a special role, and one assumes that it ought to be held to a higher standard.