There is no commentary, it is simply Presidential candidates John McCain and Barack Obama's views on a variety of topics in their own words, they have done six of them so far and plan to continue.
Here are the links to the individual articles they have published so far from oldest to newest:
IN THEIR OWN WORDS: Barack Obama and John McCain on Roe v. Wade, abortion
IN THEIR OWN WORDS: McCain and Obama on Iraq
IN THEIR OWN WORDS: Obama & McCain on the Supreme Court, judicial philosophy
IN THEIR OWN WORDS: John McCain & Barack Obama on the energy crisis
IN THEIR OWN WORDS: Barack Obama & John McCain on immigration, border security
IN THEIR OWN WORDS: McCain, Obama on 'gay rights'