How did james buchanan respond as the secession crisis loomed over the final weeks of his presidential administration?

He responded by doing nothing, Buchanan remained in Washington and did nothing which is why his presidency is considerd by many historians as a failure.

James Buchanan who was born in 1791 was the 15th president of the United States of America. His failure to stop the southern states drive to the secession is what he is known best for.