Providing information is the primary tactic employed by interest groups. A substantial portion of the legislation introduced into Congress is written either entirely or in part by interest groups. Why would members of Congress introduce such legislation?
There are two main reasons why members of Congress would introduce legislation written in whole or in part by interest groups. One reason has to do with time and expertise. The other has to do with trust and political affinity.
The first reason that members of Congress would submit such bills, rather than writing their own, is because they do not necessarily have the time or the expertise to write the bills themselves. Members of Congress have limited time and resources. They are typically members of a number of committees and subcommittees. They have to participate in those groups’ activities as well as things like floor debates. They have to consider large numbers of proposed bills every year. They have to engage in fund raising and other election-related activities. They do have staff, but they do not have many staffers compared to the amount of work there is to be done. In addition, members do not always have the expertise and knowledge needed to put together a whole bill on a given subject. They may know a little about the subject, but they are not thoroughly expert in it. Because they lack the time and the knowledge to write the bills themselves, they submit bills that are written for them.
The second reason has to do with trust and affinity. If a member of Congress is conservative, for example, they are likely to trust the National Rifle Association and they are likely to feel a connection to that organization. They might also be tied to it through campaign donations that it provides to them. Because they trust the NRA, they will not fear that it is writing a bill that they do not like. Because they feel connected to it and they need its money, they might also feel obligated to introduce the bill.
In general, then, members of Congress will do this because it saves them precious time and effort and because they trust the interest groups and/or feel that they owe the groups some loyalty.