Comment on this statement by an official of the Federal Reserve:

[the Fed] can control nonborrowed reserves through open market operations [but] it cannot control total reserves, because the level of borrowing at the discount window is determined in the short run by the preferences of depository institutions.

Quoted from Alfred Broaddus, "A Primer on the Fed," Chapter 7 in Sumner N. Levine (ed.), The Financial Analyst's Handbook (Homewood, IL: Dow Jones-Irwin, 1988), p. 194.