@Baseman, please kindly conduct some research. Any country sanctioned by the United States prohibits US-based companies, including ExxonMobil, to conduct business in such sanctioned country.
Please research OFAC - Office of Foreign Assets Control, for further information. In fact, ExxonMobil recently was fined and had to withdraw from an oil discovery deal off the coast of Siberia after it was fined by the U.S. Treasury for engaging in business with a country that was on OFAC's economic sanctions list.
There are different types of sanctions under OFAC. What is being called for by the PPP/C is an economic sanction against Guyana should Granger stay in power. Please provide me a list of countries that a United States-based company still conducts business with where an economic sanction is currently imposed? I'll wait.