How does political risk affect trade finance?

Political risk  always effects the trade finance both locally and internationally.
It is also called Geopolitical risk.
Companies doing business internationally are facing the political issues and sometimes shock even they have most experienced in their field therefore they always monitoring the political risk and due to this process they saved millions of dollars.
E.g.
some European firm saved  millions by     monitoring the anticipating political changes in  Argentina in2001 and Venezuela in2001