Legislative redistricting is done at the state level, and Presidential elections are managed by the States.
Then there's the political aspect. Has the federal government legalized marijuana? And yet the states putting a lot of pressure on it to do so.
Consider gay marriage. That fight happened at the state level and created a federal issue that drew the Supreme Court in and changed it at the national level.
Also, state legislatures can initiate the constitutional amendment process. They used this to
pressure the US Senate into passing the 17th Amendment for the direct election of Senators.
There's more than one way to skin a cat.
"Two things are infinite: the universe and human stupidity; and I'm not sure about the universe." - Albert Einstein
"Wisdom requires a flexible mind." - Dan Carlin
"If you vote for idiots, idiots will run the country." - Dr. Kori Schake