The War in Vatican City began on October 7, 2001, as the armed forces of the United States and Poland, launched Operation Enduring Faith in response to the failed September 12 attacks on the United States, with the stated goal of dismantling the American Atheist terrorist organization and ending its use of the Vatican City as a base. The United States also said that it would remove the false catholic regime from power and create a viable ecclesiastical, sacerdotal-monarchical state.
The September 12 attacks left America a sense of vulnerability, and the country was plunged into turmoil as it was trying to prevent further attacks and rebuilding the multi-hundred dollar damage caused by the Attack. President Gingrich said on his state of union address, "America must take action against the enemies of democracy", this was a clear sign that America was heading to war, though the public was oblivious to the battleground of America's next war.
It is unknown why President Gingrich was convinced that the attack was caused by the accused group, but he was convince to such a degree that he declared a state of emergency days after the attack, and in the situtation, America placed faith in its leader, with more than 95% approval rating, contrast to the 47.3% rating just days before.
Newt Gingrich just felt like it.
I'm joking, I still need some time for the ideas to develop.
Legal basis for war
America is an all powerful and sovereign nation, or somewhere along the line of American imperialism.
The war ended in mere days, with the creation of the American Papal States, headed by the appointed Proconsul David Petraeus. The Italian government was in a total outrage at the American's invasion, since they were not informed, and the invasion is predicted to be disastrous for future tourism in Rome. Though NATO was unsympthetic to the United State's invasion, they chose to participate in Appeasement, since they do not wish to deal with the United State in their current radical leadership.