Senate and congress members can have direct influence in the passing of the laws. They're the one who make the proposals of the vast majority of legislations and conducted the votes to determine which law proposal should be actualized.
The President of United States could create laws through Executive orders. These orders will be treated similarly as the legislative proposal from the Congress. The orders could only be overturn if the Judicial branch determine they're unconstitutional or members of the congress rejected it with supermajority of the votes.
Individual citizens do not have the ability to be directly involved in creating the law. But, they can choose the government representatives who are directly involve in it. So, these citizens can make suggestion to those representatives and they have to follow it if they wanted to keep their position in the next election.
Supreme Court decision that upheld the separate but equal doctrine, the case stemmed from an 1892 incident in which African American train passengers Homer Plessy refused to sit in a car for blacks.
