In the two decades before the financial crisis, there was remarkably little partisan or ideological disagreement among economists about how the Federal Reserve should conduct monetary policy. Liberals and conservatives both wanted to keep inflation below about 2 percent and unemployment below about 5 percent. Disagreements were over nuance and timing, not about overall direction. But this week, economists with Republican ties are running newspaper ads warning that the Fed's decision to pump an extra $600 billion into the economy - "quantitative easing" - will debase the dollar and spur inflation. Economists with Democratic leanings say the real danger is the opposite: deflation and double-digit unemployment.