Though your comment about pledging allegiance to the Republic sounds somewhat reasonable, I suspect that what you have in mind for the Amerikan Republik is markedly different from the ideas set forth by the founders. We can debate specifics if you like, such as the drug war, education, and the income tax.
More importantly, though, there exists a difference between loyalty to a country (which is rooted in not just a love for the principles the country is founded upon but also an ADHERENCE to those principles, as opposed to giving mere lip service to upholding some hollow oath to the Constitution just before passing a prescription drug benefit) and pledging allegiance to a country. The founders spoke often of love for one's country and most definitely recognized the concept of loyalty (treason is certainly a crime). However, you'll find that the idea of pledging allegiance to a symbol was not what they held dear. Above all, they held the idea of a true Republic, which actively defends the liberties of the individual, to be sacred - not some hollow symbol of ideas that once existed. There's a difference, and if you can't see that, then you don't really understand the concept of liberty to begin with.