Is Conventional wisdom in politics ever wrong?

The last time I can remember that conventional wisdom on all sides was wrong, where left, right, center all agreed and got fooled was when then candidate Obama lost the New Hampshire primary to Hillary Clinton. No one thought the polls were wrong. Everyone thought Obama would win.

That was years ago.

Now, everybody expects the Republican debt plan put forward by Speaker Boehnoir to pass. Even though right now he doesn't have the votes, there's no way Republicans would dessert their Speaker in a political vote right?

The plan is to pass the Republican plan, put pressure on Senate Dems, show strength and then compromise on as favorable terms as possible.

But there are apparaently House Tea Party types who don't won't to compromise or be apart of the process.

Imagine if Nancy Pelosi couldn't pass Iraq war funding because many of the new freshman in 2007 had run on ending the war and no more funding?

I figure it will go as planned, but just wanted to wonder...