I have a British and US passport and am traveling to Thailand at the end of December, 2013. I recently noticed that my US passport expires in June 2014 and Thailand has a six month rule for expiration on passports when entering the country. Not wanting to pay to have my passport expedited, I'm wondering if there is anything stopping me from leaving the US on my American passport, showing my British passport when entering and leaving Thailand, and then showing my US passport when I return to the US. Or leave the US on my British passport, enter and leave Thailand on my British passport, and then re-enter the US on my US passport. I do not need a visa because I am only going for two weeks but I do need to know about the passport dilemma! Any help is appreciated! Thanks!