Why was Jefferson worried about French control of the Louisiana Territory?

The purchase to which you are referring is the Louisiana Purchase; this was one of the largest land acquisitions in American history in which Jefferson bought the Louisiana Territory from France.

interest groups send representatives to state capitals and to washington, d.c. to put pressure on members of congress and other policymakers. they engage in lobbying, or the organized process of influencing legislation or policy. lobbying can take many forms. interest groups can testify in congressional hearings.