If countries don't tackle fiscal problems, monetary policy will be "become utterly irrelevant," former Federal Reserve Chairman Alan Greenspan said Friday, as investors try to figure out whether the central bank will increase interest rates for the first time in nine years at its meeting later this month.

Gridlock by Democrats and Republican on solving the problems posed by the spiraling costs of entitlements, namely Social Security and Medicare, has created a situation the Fed can't solve, Greenspan said in an interview on CNBC. "Both [parties] have been afraid to touch the third rail of politics."