My guess is, I think the international firms and financiers would invest in the US only when they know the future of US economy is strong enough to guarantee the returns are safe and good - better than alternatively investing in other projects in other countries.
Therefore, the fundamental issue is there must a plan for a strong US economy with strong employment, so that people would have money to spend on the new infrastructure like the fast trains or green housing from China.
Attracting worldwide tourists and students travelling to the US with open arms and friendly mind would be vital. imo. Because these people would be potential investors and migrants in the future.