The Supreme Court says federal judges cannot indefinitely delay a death row inmate's federal appeals to see if the convict can become mentally competent enough to help his lawyer.

The high court unanimously ruled Tuesday against Arizona death row inmate Ernest Gonzales and Ohio death row inmate Sean Carter.

Inmates appealing state death sentences to federal court have a right to a lawyer. But the courts never said whether the inmates have to be mentally competent enough to help their lawyers with their federal appeals. Gonzales and Carter wanted the high court to say that federal judges have discretion to hold up proceedings indefinitely until the inmates are ready.

Justice Clarence Thomas says "at some point, the state must be allowed to defend its judgment of conviction."