I don't see any problem with the pledge. Much of the rest of the world sees the US as a force for good and for liberty.
Our foreign policy has obviously been derailed the last several years. Because of the invasion of Iraq, many countries have even said they believe we are more dangerous than al Qaeda and publicly ask "who’s next". Add the invasion to the US standing by and watching the murder of the Christians in Iraq and it's understandable.
But generally, we are viewed as the land of opportunity and a place where people can be safe.
With the election of President Obama, certainly the rest of the world feels safer. He doesn't seem to be a man who is guided by his "gut". I can't imagine him giving unwanted public massages to leaders of other countries or saying, "I looked into his eyes and saw his soul". Can you?
Now I know someone is going to scream about a man who was in the Marines and the Navy Medical corps and was Valedictorian and was part of President Johnson’s surgery team and received 3 White House commendations because he was close to Obama. The right calls him a radical. If only the right had more "radicals".
So, because the US is a force for good, invasion and torture excluded, it's ok to pledge to defend it.