Headed to Des Moines today for the "Ready for Change, Ready To Lead" rally featuring Sen. Hillary Clinton and former President Bill Clinton at the Iowa State Fairgrounds tonight.

On Tuesday and Wednesday, this column will follow Barack Obama on a two-day bus tour of Eastern Iowa.

One backdrop for these Independence Day events is London.

If we in the United States are in for -- as ABC News's sources suggest a summer of terrorist threats and fear, the Democrats will begin to debate these sacred questions in earnest.

If sleeper cells are to blame for the fizzled car bombs in London and the Glasgow jeep crash, we are in for a summer of questions about the efficacy and necessity of wiretapping, about the emphasis on law enforcement techniques versus offensive military action, about secrecy and operational security, about fiscal priorities, and, least importantly, about the language we use to describe the methods by which we fight.