Vice President JD Vance arrives at the Capitol in Washington on Tuesday morning, July 1, 2025, prepared to cast a tiebreaking vote in the Senate on President Donald Trump’s sweeping tax and domestic policy bill. (Tierney L. Cross/The New York Times) By LYDIA POLGREEN Journalist Michael Kinsley once defined a political gaffe as when a politician inadvertently speaks the truth. Last week, Vice President JD Vance posted a classic of the form on the social platform X, part of an attempt during an…