STUART ROTHENBERG: Democrats Are Headed off Their Own Cliff: Instead of trying to control the center, Sanders takes his party to the extreme.

Political observers – yes, including myself – have argued for years that the Republican Party has moved too far right, allowing its most ideological elements to limit its legislative options, prevent it from addressing national problems, and damage its appeal to key swing and emerging voter groups.

But instead of Democrats responding by positioning themselves in the political center where they could maximize their appeal, many Democrats are embracing their own version of ideological extremism.

Bernie Sanders’ uncompromising anti-business rhetoric and agenda, combined with the energy of “progressive” forces in the Democratic coalition, reflect a significant turn to the left by a party that once stood for pragmatic change, not “revolution.”

Though the Vermont senator’s supporters won’t like to hear it, Sanders has plenty in common with both Donald Trump and Ted Cruz.

Like Cruz, Sanders is an ideologue who resists compromise. And like Trump, Sanders has simple answers to complex problems and sounds as if he doesn’t appreciate the dramatic, and often deeply unsettling, consequences that his policies would produce.

“Break up the banks,” roars Sanders, as if that would solve part of the nation’s economic problems without creating any new ones.

“It’s Time to Make College Tuition Free and Debt Free” asserts Sanders (on his website), without discussing the ramifications of doing so or acknowledging the true cost or the inevitable disruptions.

Anyone interested in the ramifications of some of Sanders’ proposals – and why it would be difficult to try to turn the United States into Denmark – should read Pulitzer Prize-winning columnist Steven Pearlstein’s excellent piece, “What Bernie Sanders Would do to America,” in The Washington Post. Pearlstein, who once worked for Massachusetts Democratic Rep. Michael Harrington, dissects many of Sanders’ proposals.

I blame the hormones in the water supply. The entire country has PMS.