A Trojan attack maliciously modifies, alters, or embeds unplanned components inside the exploited chips. Given the original chip specifications, and process and simulation models, the goal of Trojan detection is to identify the malicious components. This paper introduces a new Trojan detection method based on nonintrusive external IC quiescent current measurements. We define a new metric called consistency. Based on the consistency metric and properties of the objective function, we present a robust estimation method that estimates the gate properties while simultaneously detecting the Trojans. Experimental evaluations on standard benchmark designs show the validity of the metric, and demonstrate the effectiveness of the new Trojan detection.