Is the judiciary unchecked?

From Slate:

"When a federal judge ordered 17 Chinese Uighurs, detained at Guantanamo Bay, released into the United States last October, he took to its logical conclusion the judiciary's increasingly bold effort to supervise the president and Congress. Justifying his ruling in the face of Congress' exclusive constitutional power over when, which, and how foreign nationals may enter the United States, Judge Ricardo Urbina reasoned that "our system of checks and balances is designed to preserve the fundamental right of liberty." He saw his order as necessary to that end. But if he's right, then the judiciary itself is the unchecked branch of government. And while judges have expanded their power before in our history, never have the claims to supremacy of some of them been so extreme."