(CNN) The death of Arizona Sen. John McCain has occasioned a number of heartfelt tributes as the nation pays homage to a man who sacrificed much for this country. But how will McCain be remembered in the Senate, the place where he spent the final 30+ years of his life? And how do his legislative accomplishments rank against the list of our greatest senators?

I put those questions -- and more -- to Ross Baker , professor of political science at Rutgers University and someone who has spent considerable time in the Senate as a senior adviser to both Sens. Patrick J. Leahy (D-Vt.) and Chuck Hagel (R-Neb.).

Our conversation, conducted via email and lightly edited for flow, is below.

Cillizza: Let's start with a simple word association: When you think of "Sen. John McCain," what words jump to mind -- and why?

Baker: Irascible but lovable. A keen mind and a hot temper. And a junk food addict.