There were reelections in the state houses for one third of the senators just 2 years after the constitution was ratified, but why were these senators chosen to go up first. The constitution gives the senators 6 year terms, but it also stipulates that a third goes up for reelection every 2 years, so how was this done? I can't find any good sources on this question anywhere, and my professors didn't know. Any help appreciated
According to George Haynes' The Senate of the United States assigning which class each senator would belong to, was one of the first actions the senate undertook, after electing leadership, establishing rules, etc.
They adopted a rule that no state would have senators belonging to the same class. They then literally drew lots in May 1789 to assign the classes. There were four senators that didn't get elected until later in 1789. Because they hadn't been elected in time, they drew their lots upon taking up their offices.