Though he denies using that exact phrase, in arguing against what became the disastrous 2003 US attack on Iraq Powell made the point that, as in Pottery Barn, "if you break it, you own it."
Bush and his neocons – ironically with the help of Colin Powell himself – did indeed break Iraq and the American people as a result "owned" Iraq for the subsequent 22 years (and counting). It was an idiotic war and, as the late former NSA chief Gen. Bill Odom predicted, turned out to be "the greatest strategic disaster in American history."
Attacking and destroying Iraq – and executing its leader – not only had no value in any conceivable manner to the United States, it had negative value. In taking responsibility for Iraq's future, the US government obligated the American people to pick up the tab for a million ransacked Pottery Barns.