The practice in which members of Congress agree to vote for a bill in exchange for their colleague's vote on another bill is called

The practice you're referring to is known as "logrolling." This involves reciprocity between legislators, where one member agrees to support another member's proposal or bill in exchange for that member's support on their own legislation. Logrolling can be an effective way to ensure that legislation passed in Congress has enough support, especially when issues are highly specific or specialized.

In this context, logrolling helps facilitate cooperation and negotiation among members, allowing them to build coalitions and leverage their votes for mutual benefit. This practice highlights the importance of strategic voting and the interconnectedness of legislative interests, where the passage of one bill may hinge on the agreement to support another. However, it can also lead to the passage of legislation that wouldn't necessarily have widespread support on its own, raising concerns about accountability and the quality of the laws being enacted.