The fourth section of Article I establishes some basic guidelines for congressional elections and for Congress’ meetings.
The first clause describes the delegation of power between the federal government (Congress) and state governments regarding elections to Congress. According to this clause, states are permitted to set different laws for their respective elections. But Congress may also make such laws and override essentially any state laws to the contrary.
This second clause, today, is mostly moot. It requires Congress to meet at least once a year. The limits of communication and travel in the 18th century were so burdensome that a constitutional requirement that Congress gather one time in a year was necessary. But today, being a Senator or Representative is a full-time job in Washington, D.C. and Congress meets regularly throughout the year. Additionally, the last piece of this clause – that if Congress were to only meet once a year, that day should be the first Monday in December – was superseded by the 20th Amendment
. Now, Congress must meet, at least, on January 3rd.