Of course, Trump's critics leapt immediately to the attack

President Trump granted a pardon to Michael Flynn, his former national security adviser, Wednesday. Flynn had pleaded guilty to lying to FBI agents about conversations, during the 2016 transition, with the Russian ambassador about sanctions. Flynn's pardon should bring to an end one gross violation of the Constitution's separation of powers, even as it gives rise to groundless accusations of another.

Although Flynn had pleaded guilty, the circumstances of the case had raised serious concerns about whether the government had proceeded properly. The FBI, for example, questioned Flynn even though it did not appear he had violated any law.

In May, Attorney General William Barr ordered the case dropped. Under the Constitution, only the president has the responsibility and duty to see that "the Laws be faithfully executed." From this clause flows the executive branch's prosecutorial discretion — the sole right to decide what cases to prosecute or not.

As I explain in my book "Defender in Chief: Donald Trump's Fight for Presidential Power," in normal times, a president's decision to drop a prosecution is final and unreviewable by any other branch.

But these are not normal times. In yet another example of yet another institution willing to twist yet more rules out of resistance to Trump, the federal courts would not accept the president's exercise of prosecutorial discretion. Instead, federal judge Emmet Sullivan refused to allow that the Justice Department had dropped the case, and the full federal Court of Appeals in Washington, D.C. upheld his decision.

These judicial antics intrude into the president's sole authority to enforce the law, and also pull the courts beyond their limited constitutional role to only decide cases or controversies between parties.

President Trump's pardon not only ends any injustice to Flynn, but it restores the proper balance to the separation of powers. Courts will no longer claim the right to direct a prosecution that even prosecutors no longer wish to bring.

Under the Constitution, courts are to decide cases or controversies, not to create them. The pardon restores the right of future presidents to direct prosecutions, including choosing the cases that represent the best outcomes for the use of limited federal resources.

Of course, Trump's critics leapt immediately to the attack. House Intelligence Committee chairman Adam Schiff, D- Calif., said Flynn had chosen "loyalty to Trump over loyalty to his country" and Trump's decision was intended to insulate himself from criminal investigation.

Schiff called that a "corruption of the Framer's intent" in giving the president broad pardon powers. "It's no surprise that Trump would go out just as he came in — crooked to the end," Schiff said.

House Judiciary Committee Chairman Jerrold R. Nadler, D-N.Y., called the pardon "undeserved, unprincipled, and one more stain on President Trump's rapidly diminishing legacy."

John Yoo: Trump pardon of Flynn ends unjust prosecution of former national security adviser | Fox News