Lobbying is "directly advocating for or against particular legislation or regulations." Writing your representative is lobbying. Fighting bad legislation is lobbying. Any good faith attempt to argue a position on a government policy is lobbying.
Giving money to politicians or their campaigns is not lobbying, and it is already illegal for lobbyists to do so.
What could and should be made illegal is allowing unlimited political campaign donations via Super PACs. Political donations aren't lobbying.
It's worth being clear about what you actually want to make illegal because you probably don't want to ban anyone from arguing a political position.
It's one thing when a bill on technology is misunderstood by regulators and insiders provide context on unintended consequences, another when checks are written such that the voice of polluting industries outweighs voters' desire for clean air and water.
Giving money to politicians or their campaigns is not lobbying, and it is already illegal for lobbyists to do so.
What could and should be made illegal is allowing unlimited political campaign donations via Super PACs. Political donations aren't lobbying.
It's worth being clear about what you actually want to make illegal because you probably don't want to ban anyone from arguing a political position.