Final answer:
Gingrich's denial of the racial basis behind terming Obama as the "food stamp president" exemplifies the third move of racial dog whistling as outlined by Ian Haney Lopez, which is the act of making a racist statement and then denying its racial intent.
Step-by-step explanation:
In Ian Haney Lopez's Dog Whistle Politics, he describes racial dog whistling as a political tactic that uses coded language to appeal to certain sentiments without overtly relying on racist terms. Newt Gingrich referring to President Obama as the "food stamp president" and subsequently denying any racial implications is an example of the third move of racial dog whistling. This move consists of making a racially charged statement and then denying its racial underpinnings, a tactic which allows politicians to mobilize racial tension without being directly accountable for racism.