Delaware constitution
Article II
Section 14

No Senator or Representative shall, during the time for which he shall have been elected, be appointed to any civil office under this State which shall have been created, or the emoluments of which shall have been increased during such time. No member of Congress, nor any person holding any office under this State, or the United States, except officers usually appointed by the courts of Justice respectively, attorneys-at-law and officers of the militia, holding no disqualifying office, shall during his continuance in Congress or in office be a Senator or Representative; nor shall any person while concerned in any army or navy contract be a Senator or Representative.