“You know that if the President is re-elected, he will still be unable to work with the people in Congress,” Romney said. “He has ignored them, attacked them, blamed them. The debt ceiling will come up again, and shutdown and default will be threatened, chilling the economy.”
Despite the apocalyptic warnings on the economy, most of the Republican nominee’s speech focused on a more modest argument that as president he would work with both sides to build a stronger economy. He said that, like Obama, “I promise change, but I have a record of achieving it.”
Note the passive voice at the end of that first paragraph: "The debt ceiling will come up again, and shutdown and default will be threatened, chilling the economy." That debt ceiling will rise on its own, and the threats will just appear out of nowhere! They can't be stopped!
Except, that's not how it works. Threats don't materialize without someone to make the threats. In this case, Romney's party is doing the threatening, which means that Romney, as the face of the Republican party, is making this threat. He's essentially trying to take America's future hostage. This is low, even for Romney.