Under George W. Bush, oil stocks became gushers. Technology stocks lit up during the Clinton presidency. So which shares would rise the most during a Barack Obama stretch in the White House? It’s actually easier than it might seem to pick the right investment themes for a politically charged run. After all, you didn’t need to be Warren Buffett to figure out that Exxon Mobil or Chevron would benefit from a Texan president, or that defense stocks would flourish under Reagan.