I am not a Mitt supporter. I don't know what he says on the stump. The subject of China and trade has come up a number of times at the debates and all the candidates talked about how they would crack down on them for currency manipulation, unfair trade policies, etc. using sanctions and the like. They all, including Obama, like to talk tough when it comes to China when on the campaign trail, but in the case of Obama, do nothing.
I guess when someone holds $1 trillion of your debt, you are a little more cautious about what you say and do when you are in power and can actually do something.