Welcome to Malta, dead center in a huge geopolitical struggle between East and West. The Turks are threatening to invade the defenseless city, and Ferneze is making deals left and right to try to make sure Malta doesn't get torn apart. By the time The Jew of Malta ends, you're left wondering what exactly makes a good politician—and it may not involve squeaky-clean ethics. Politics are so relentlessly brutal that only those who are willing to break the rules can survive, much less ensure civic harmony. In the game of Maltese politics, you win or you die.
Convenient hypocrisy and deceit, of the kind you see employed by Ferneze, is ultimately shown to be the only way to ensure stable government.
Marlowe ultimately suggests that force and violence aren't great ways to gain political power.