Fördragen the EU's basic rules

What The treaties (fördragen) are the EU's basic rules, which set out what the union may do and how decisions are to be made, much like a constitutional law.

Who Politicians in the member states' governments and parliaments, who together negotiate and approve the treaties.

How You make a difference indirectly via the general election (to the Riksdag), because Sweden's government and Riksdag help to negotiate the treaties.