While the word Senate is capitalized, the role itself is lowercase when referring to a general senator or senators. However, if you refer to a specific senator by name, then you need to capitalize it.

Is Senate and senator capitalized?

These terms may only be used to refer to members of the U.S. House of Representatives; for members of the U.S. Senate, use the word senator. Capitalize these words when they appear as a title before a name.

Does House and Senate need to be capitalized?

Capitalize “U.S. Congress” and “Congress” when referring to the U.S. Senate and House of Representatives. Although “Congress” sometimes is used as a substitute for the House, it properly is reserved for reference to both the Senate and House.