Benny, it’s inspiring to read how Joni Ernst, fresh off her grueling Senate campaign, reported for National Guard training this week. It remains to be seen how she will balance her Senate duties with her military obligations, but Senator Lindsey Graham (R., S.C.) is an Air Force reservist who has managed to work the occasional overseas tour of duty in between Senate sessions.

Earlier wars have also seen elected national officials take time off to serve. In 1940 Representative Lyndon B. Johnson was commissioned an officer in the Naval Reserve, and shortly after Pearl Harbor, he was activated and sent to assess production facilities stateside and investigate conditions in the Pacific theater. He spent several months on active duty before returning to the House.

But the highest-ranking government official to serve during wartime was Hannibal Hamlin, Lincoln’s first-term vice president. In the summer of 1864, his Coast Guard unit in Maine was called up, so he reported for duty at Fort McClary, at Kittery Point. The vice president of the United States spent two months in active military service, first as a guard and then as a cook. He seems to have enjoyed his service; as VP he had little to do in Washington even during wartime, and he had already been passed over for a second term in favor of Andrew Johnson.

For the record, this law professor lawyer thinks it’s unconstitutional for a member of Congress to serve in the armed forces, even as a reservist, under Article I, Section 6, Clause 2: “No Person holding any office under the United States, shall be a member of either House during his Continuance in Office.” Robert Bork disagreed with him, and without having read the whole paper, I’m inclined to trust Bork on this. But the paper has much valuable historical background and examples of military officers who served, or attempted to serve, in Congress.

UPDATE: Professor Seth Tillman, of Ireland’s Maynooth University, points out that the author of the paper linked above was not and is not a law professor, but rather a practicing lawyer.