PACs and super PACs are the key difference. Lobbying in the US includes practices that would fall squarely into the definition of corruption in many other Western countries.
There's nothing inherently wrong with people or groups talking to representatives and advocating for their interests, even in an organized way. The problem is when it gets closer to: "Pass this law or regulation, and we'll put $USD_AMOUNT into your PAC".
There's nothing inherently wrong with people or groups talking to representatives and advocating for their interests, even in an organized way. The problem is when it gets closer to: "Pass this law or regulation, and we'll put $USD_AMOUNT into your PAC".