What is the main idea of this passage? [br] [originaltext]A libertarian think t

A libertarian think tank, reckon that eliminating all travel visas to the United States would add between $90 billion and $123 billion in annual tourist spending. By one estimate, introducing visa restrictions can lower trade and foreign direct investment between a pair of countries by as much as 25% .

After years of trying fruitlessly to prop up energy markets, OPEC on Wednesday finally reached a consensus on production cuts, sending oil prices soaring. The problem is, the euphoria in the markets may not last. With prices still at less than half the levels of two years ago, the Organization of the Petroleum Exporting Countries agreed this fall to lower collective production. But it could not figure out how to spread the cuts among the countries.