A US president can't really do much to influence gasoline prices, but this year's Republican candidates insist that he can, and two-thirds of the voters believe them. So President Obama will devote three days this week to an energy tour of the country, emphasizing what he claims is solid energy policy. What are the major factors leading to recent increases in the price of gas at the pump? Are the oil companies exploiting opportunities for domestic drilling? Did the President blow it by delaying development of the Keystone XL Pipeline?