Defense!

As part of the debt ceiling fight, there's a "trigger" mechanism that will induce automatic cuts if lawmakers can't agree to other cuts come December.

Those cuts: largely focused on Medicare and defense.

Hence, defense stocks are among the big losers today.

Here's PPA, the PowerShares Aerospace And Defense Portfolio ETF.

That big red bar (via StockCharts.com) tells you all you need to know.