In a series of decisions on campaign finance legislation, the Roberts Court has made it clear that Congress cannot solve the enduring political issues of undue or unequal influence in politics by restricting speech. Now that legislatures are aware this option is no longer on the table, they are under more pressure to find other solutions. Importantly, Congress could constrain undue influence by legislating through rules of general applicability.
Under a regime of generality, Congress would disable itself from handing out money, lucrative projects, or regulatory relief to designated individuals or small groups. Such strictures would make corruption less likely and indeed eliminate the kind of influence which seems most undue. Decisions that that can be framed in terms of general rules are more likely to be aimed at the public good than at the provision of favors.
In fact, Congress recently moved toward legislating through general rules by eliminating earmarks.