The Solicitor General of the United States is the attorney for the government who presents briefs and oral arguments before the U.S. Supreme Court. The person who holds this position, thus, makes more frequent — and more important — appellate arguments than just about anyone.
Often, the U.S. Solicitor General is later appointed to the United States Supreme Court, the earlier job being both a proving ground for that important position, and a place from which the holder can become known to the President of the United States, who makes such appointments.
Thus, I got a chuckle out of this quote from former Solicitor General Robert H. Jackson, who himself was appointed to the U.S. Supreme Court by President President Theodore Roosevelt. (As a side historical note, Jackson is the only man to have held all three jobs as U.S. Attorney General, U.S. Solicitor General and Supreme Court Justice.)
“I used to say that, as Solicitor General, I made three arguments of every case. First came the one that I planned–as I thought, logical, coherent, complete. Second was the one actually presented–interrupted, incoherent, disjointed, disappointing. The third was the utterly devastating argument that I thought of after going to bed that night.”
This is, of course, precisely what appellate advocacy is like.