"Pleading the fifth" (amendment), is such common chorus in American culture, it's near cliché by now. We hear it on television, from every tv cop to the real-time reports on testimony from gangsters, disgraced bankers and bureaucrats alike.

Even grade schoolers know the Constitution reads, in part, "No person shall… be compelled in any criminal case to be a witness against himself…."

This applies to taxes too, right?

Not so fast.

For proof, look at Lois Lerner, former head of the IRS Exempt Organizations Unit. Congress subpoenaed Lerner to testify after evidence emerged her unit had targeted conservative non-profit organizations. In each of her appearances, she invoked her Fifth Amendment right against self-incrimination.