Pat Buchanan is a traditional republican. He makes the distinction that neocons that now run the Republican party are not true republicans. True republicans like Eisenhower were against US involvement in foreign wars, especially against those countries that were not a direct threat to the US, and also were against the close association between big corporatioins and politicians. Also, it was Democrats that got the US involved in Vietnam. It was also Nixon, a Republican, that got the US out of Vietnam, and opened the door to Red China; if the neocons had been in power then, it would never have happened.
Some say that, in reality, the Neocons are Leninists: that's the spreading of a doctrine throughout the word through military force.