But when asked for specifics to support your claim you brought up that Gavrilo Princep was a jew, Leon Trotsky was a jew, and mentioned zionism.

I addressed that already. I posted a couple of paragraphs, but you decided to reduce it all to the first statement, taking it out of the context of the whole and ignoring the rest and thus strawmaning the argument as if the whole argument is build around the speculation that Gavrilo Princep is jewish.

As for Trotsky, it is definitely significant that he was jewish considering 90% of the bolsheviks were jewish and were financed by jewish banks in the West.

So we have a jewish ideolog (Karl Marx), jewish revolutionary leaders (Lenin, Trotsky, Kerensky and Zhinoviev) and jewish financiers (Wall str's Jacob Schiff, of Kuhn Loeb and Co., Chase Manhattan Bank of the Fed, J.P. Morgan). Then we have the Protocols of Zion which is a blueprint for the revolution and the subsequent regime. How is the bolshevik revolution not a jewish conspiracy to seize control of Russia (and other European countries, where the communist revolutions and short-lived regimes failed miserably)? Moreover, this was not their first rodeo in bringing about a communist NWO and previously both the English and the French Revolutions where planned, organized and executed by jews (and their useful pawns).

Is it accurate and fair to describe the mafia as "An Italian conspiracy to rule New York"? Why or why not?

No. The mafia does not hold a nationalistic agenda - as I said they are a criminal secret society originating from Italy. The mafia was a conspiracy of Italian criminals to rule over New York criminal world and influence the government. Calling it an Italian conspiracy would suggest the Italian government and elites supported their efforts in the US, which they did not. Subtlety of language is key for context.