Trump's biggest nightmare isn't Mueller

As accomplished and respected as Mueller is, the SDNY has important structural advantages. While Mueller is limited by his appointment to investigating coordination between Russia and the Trump campaign (and matters that “arise directly” from such coordination), the SDNY has no substantive constraints and can go wherever the evidence leads.

Mueller faces political pressure from Trump and the Department of Justice to finish his investigation; the SDNY isn’t going anywhere and can take whatever time it needs. The SDNY is also not subject to the special counsel regulations, which require attorney general approval for major prosecutorial decisions and through which Mueller ultimately must filter his findings.

And, unlike Mueller, the SDNY cannot be fired or defunded; sure, Trump could fire the US attorney for the SDNY, but there will still be 150-plus apolitical career prosecutors ready to carry on.

Take it from an alum, the SDNY is uniquely tenacious and relentless.