“It's illegal to comment on political matters on your official profile,” said a source familiar with congressional ethics rules. “It's also bad practice because it confuses constituents on which is political and which is official. The news of a VP pick has nothing to do with your elected official duties.”

There is a handbook dedicated to the rules for proper governmental use of resources, including communication tools such as social media. The complexity of these rules also explains why many offices steer clear of sending out tweets that express any opinion outside of a press release. But last weekend, when social media was the fastest — and for many, likely the only — way to react to the news of Romney’s new VP, several offices apparently forgot the rules.

The Sunlight Foundation noted the likely breach in applicable rules governing social media use in a blog post on Wednesday night.

"While political tweets on official accounts are not the worst offense a member can commit, the point of this rule is to separate the official actions of Congress from politics and to prevent public resources from being used for campaign activity," Melanie Sloan, executive director for the watchdog group Citizens for Responsibility and Ethics in Washington (CREW), told Sunlight Foundation. "It is fine for members to express their political views on social media. They just shouldn’t do it on their official accounts.”

Many members of Congress have separate Twitter accounts for campaign and official use, but the separation can get confusing for both them and their followers. The information is usually included in the Twitter account bio, and typically official Twitter accounts are verified through Twitter (marked with the blue “check” on the bio) while campaign accounts are not.

But Rep. Justin AmashJustin AmashEx-GOP lawmaker says Trump 'illegitimate president,' should be impeached Ex-GOP lawmaker pens op-ed calling for Trump to be impeached On The Money: Senate passes disaster aid bill after deal with Trump | Trump to offer B aid package for farmers | House votes to boost retirement savings | Study says new tariffs to double costs for consumers MORE (R-Mich.) summed up the tension well with the hashtag “#splitpersonality.”