Yes. At least an amendment to abrogate the Citizen's United decision.
But also, a check on gerrymandering. Congressional districts should be drawn so that each House member represents as equal a number of constituents as possible. This would not require an amendment. Just an act of Congress. The Constitution gives the manner of choosing members of Congress to the states. But it also gives Congress the power to alter how Congresspersons are chosen.
Article I, Section 4:
The times, places and manner of holding elections for Senators and Representatives, shall be prescribed in each state by the legislature thereof; but the Congress may at any time by law make or alter such regulations, except as to the places of choosing Senators.