One of the themes that Governor Romney has been hitting at aggressively in his campaign ads is that he will get tough on China. The ads complain that China is a cheater, most importantly by "manipulating" the value of its currency. This means that China has been deliberately keeping down the value of its currency against the dollar.

A lower value for the yuan, which means a higher valued dollar, makes Chinese goods cheaper for people in the United States. It is the same thing as if China were to subsidise its exports to the US. On the other side, the over-valuation of the dollar makes our goods more expensive to people in China, meaning that they will buy less of them. It is comparable to putting a tariff on US exports to China.

Romney promises to be the tough guy who will reverse this situation. His ads claim that he will declare China to be a currency manipulator and take retaliatory measures. 

President Obama has responded to Romney's charges by pointing out that Romney personally has profited from dealings with China. His ads point out that Bain Capital, Romney’s former company, was a pioneer in outsourcing jobs to China.

While people will have to decide for themselves what they think of Romney's business dealings in China, the Obama ad helps to clarify the issues in US negotiations with China. The reality is that there are many US businesses that are profiting enormously from the current situation with China maintaining an under-valued currency.

At the top of this list would be retailers like Walmart who invested an enormous amount of money in building up low cost supply chains in China, as well as other countries in the developing world. These low-cost supply chains are a main source of their competitive advantage over other retailers. They will not be anxious to see this advantage eroded by a 20-30 per cent rise in the yuan, which will largely be passed along in higher prices.

In the same vein, major manufacturers like General Electric have shifted much of their manufacturing capacity to China and other developing countries. These firms will also not be anxious to see the dollar fall, making the goods they produce overseas relatively more expensive.

If a president were to demand that China raise the value of its currency, they would not only be coming into conflict with the government of China, they would be coming into conflict with the US companies that are profiting from the over-valued dollar. These companies could be expected to use all the political power at their disposal to prevent any steps that will lessen the value of the dollar against the yuan.

In fact, the domestic line-up against a lower-valued dollar is even more formidable than just the retailers and manufacturers who directly benefit from the over-valued dollar. The US has a long list of economic demands that it makes on China's government. 

Most notably it has been pressing China for increased access to its domestic market for the financial industry. This is very important to companies like JP Morgan and Citigroup. It has also been demanding that China have stronger enforcement of patents and copyrights. Stronger patent protection is important for drug companies like Pfizer and Merck, while stronger copyright protection could mean billions for Disney, Time-Warner and the rest of the entertainment industry.

If a higher valued yuan was placed at the top of the US list in negotiations with China it would mean that these other goals would get less priority. As a superpower, no one expects China to simply accept a list of demands handed to them by the US president. Inevitably there is a negotiation process and if the US gets concessions on the value of the currency, it will almost certainly come at the expense of progress on other demands.

This means that if Romney or any other president were to crack down on China over its currency, not only would he be forced to first overcome the opposition of the firms that directly profit from the over-valued dollar, he would also have to overcome the objections of many powerful corporations who want their own issues with China to be given priority.

In short, the issue is not really one of finding a president who is prepared to stand up and be tough against a cheating China, the issue is finding a president who is prepared to stand up and be tough with US corporate interests. Romney can certainly blame President Obama for not taking the tough stand against US corporations in his first term. The question is whether there is reason to believe that Romney would be any tougher on his friends and former business partners.  

Dean Baker is a US macroeconomist and co-founder of the Centre for Economic and Policy Research.