How can you debate that imperialism doesnt exist in the modern era?

There are two sides on a debate of this magnitude. That nations in the current world are not imperialisitc, and that they are. For instance, one can say that the United States has continued on a path of Imperialism since the early 1900's with our intervention in Latin American Affairs. On a more recent note, some may say the Iraq War was imperialistic in nature (aka "blood for oil"). The opposite side is simply that the United States (and many other nations) are looking out for the democracy and safety of many other nations while at the same time ensuring their own interests. The debate is long winded on either side, but both can be proven rather well.