Can Mike Pence's vow not to sling mud survive a Trump campaign?

In 1990, during a close and bitter congressional race, Mike Pence came under attack for using campaign funds to pay for personal expenses, including his mortgage and credit card bills. Pence in turn blasted his opponent with attack ads, including one featuring a man in traditional Arab clothing who thanked Pence’s opponent in thickly accented English for policies that benefited Middle Eastern oil producers. Pence, who is now Indiana’s governor and was selected this week to be Donald Trump’s presidential running mate, lost his 1990 race, but what he regretted more than losing, he later said, was his decision to sling mud.