Jason Isbell’s album “Southeastern,” from 2013, is the best thing I’ve heard in the last five years. The precision and penetration of the writing, and the world-weariness of the melodies, simply are unlike anything else today. Following such a high-water mark surely was a daunting affair, but Isbell seems to have come through. The new album, released yesterday, shares the same melancholic feel as the previous, and the razor-sharpness that has come with sobriety is still present. You’ll never hear him on mainstream country radio, but Jason Isbell is the best country artist of the day.