“USA, USA, USA!” The familiar chant of another MAGA triumph filled the New York Stock Exchange last month as Omeed Malik and Donald Trump Jr. rang the opening bell to mark the trading debut of firearms retailer GrabAGun. You could also call the company the culmination of their close personal and business relationship, the Amazon of guns, or a middle finger to anyone who is horrified that GrabAGun’s stock symbol is PEW—the sound of a bullet.

For the man standing next to Trump Jr., the scene would have been unimaginable a decade ago. Malik considered himself a lifelong Democrat, had voted twice for Barack Obama, donated to Hillary Clinton, and worked in Congress for two Democrats from New Jersey, his home state. He attended fancy parties and fundraisers alongside wealthy, well-connected liberal elites like Jack Dorsey and George Soros in New York City and the Hamptons.

But then, as Malik tells it, the Democrats abandoned and betrayed everything he cherished about them. From #MeToo to Black Lives Matter to Covid to environmental, social, and governance (ESG) policies, they embraced views that were antithetical to the most essential American ideals. As a result, “I had no choice but to do what I did,” he told me.

What he did was switch sides. Now, he is at the very center of the MAGA universe, where politics, money, and power are colliding during Trump’s second term in ways that often cause an uproar among the D.C. establishment and beyond...