The Senators and Representatives of Congress were not to hold any other ___ while in their elected office.

Office

Explanation:

The terms 'office' in this context means another position within the government Branches.

United States government system implemented a check and balance in order to limit the power of all government officials. This was made to prevent the government from becoming too powerful.

Senators and Representatives belong to the legislative branch. For example, If we allow these people to also held other position in Judicial branch , they will easily bypass the check and balance system and pass any type of legislation they want without fearing that they'll fail the Judicial review process.