First, he’s a masterful bureaucratic tactician. Unlike his predecessors, Michael Flynn and H.R. McMaster, Bolton is a very experienced and adept creature of Washington institutions. Similar to former Vice President Dick Cheney, he knows the levers and knobs of the vast national security and foreign policy machinery: how they work, who works them, and how to exert control over them. He’ll work to put loyalists in key vantage points and marginalize those he distrusts (both of which I watched him do as undersecretary of state for arms control and international security). In particular, he has the already-weakened State Department, now lacking a secretary, especially mapped out for further hostile takeover.

Second, he’s a crafty negotiator. I’ve never believed that Donald Trump is the artful dealmaker he pretends to be; he has a few plays that he just runs again and again. But Bolton is truly clever. He picks his battles much more carefully than Trump does. As U.S. ambassador to the U.N., Bolton is mostly remembered for his hostility to the institution and for his coarse bluntness. Yet in that multilateral diplomatic maze, he often delivered for the administration, including on North Korea at the U.N. Security Council.

Third, he’s thorough and methodical. Most senior policymakers simply cannot keep up with the details across so many issues. I watched Bolton dominate ICC policy meetings with mastery of the minute particulars, preserving a strategy that was more hardline—and unnecessarily costly—than I think even the president would have wanted (though I’d note that Bolton’s early victories on this issue didn’t last into Bush’s second term).