The demand that Congress honor a treaty and seat a nonvoting delegate comes amid growing clashes over sovereignty and a tight race for Oklahoma’s governor, a Cherokee citizen.
James Coddington, who was convicted of murdering a co-worker with a hammer, is the first of 25 men the state is aiming to execute over the next 28 months.
The N.C.A.A. has restricted previous events in response to state lawmakers. It faces that test again in Oklahoma, where softball championships are a mainstay and a restrictive abortion ban recently became law.