President Obama delivered a strange series of headlines Friday: There is hope that Iran will end its nuclear weapons program following initial talks between its new government and the United States, the first direct negotiations between the countries since 1979.

And the United Nations has passed a resolution requiring the government of Syria to turn over its chemical weapons to an international authority so that they can be destroyed.

But the president could report no progress with Republicans in the House of Representatives, who won’t give up their weapons of mass destruction and continue to threaten that they may shut down the government or default on the nation’s debts unless they win policy concessions from the White House on the Affordable Care Act.

These threats have been commonplace since the tea party ascendance in the 2010 elections gave Republicans the majority in the House of Representatives, but that doesn’t mean that we should not take them seriously.

A government shutdown, even a short one, would affect the millions of Americans who rely on federal services or draw a paycheck from work in the federal government.

A refusal by Republicans in the House to pass an increase in the debt ceiling could trigger a default on the nation’s debt, which in turn could send the global economy into a tailspin. There is no way to know for sure what would happen, because no one’s ever been crazy enough to try it.

Unfortunately, as former Sen. George Mitchell pointed out in a speech at the Muskie School of Public Service in Portland on Thursday, the science of computer modeling has created a House of Representatives where the seats are so safe, only a few are ever really up for grabs.

That means it’s not the election in November that incumbents have to worry about, but their party’s nominating process, in which there are no prizes for moderation. This gives a group like the tea party much more influence than it deserves.

That explains the extreme rhetoric and strange behavior coming out of the House as we edge closer to a self-inflicted economic catastrophe.

This is not the democratic republic our founders envisioned. While minority rights are one of the checks and balances that make our system of government work, no one ever intended that controlling half of one branch of government should give a minority party veto rights over every piece of public policy.

The Affordable Care Act was a major issue in the last election, and had the Republicans won the White House and a majority of the Senate, it would probably have been repealed by now. But that’s not what happened.

Now they are holding the economy hostage while they try to achieve through undemocratic means what they failed to do with the ballot. They should not be allowed to win. The U.S. government should not negotiate with terrorists, even when the terrorists are in the U.S. government.