What is the test for whether a defendant has been denied a right to a speedy trial?

We reach the constitutional issue only because violation of the Sixth Amendment would require dismissal with prejudice. See Strunk v. United States, 412 U.S. 434, 439 (1972).

Four factors determine whether the sixth amendment's guarantee of a speedy trial has been violated: the length of the delay, the reason for the delay, whether the defendant asserted the right, and whether he was prejudiced by the government's denial of it. United States v. Sears, Roebuck and Co. Inc., 877 F.2d 734, 739 (9th Cir.1989). Unless the length of delay is presumptively prejudicial, we need not examine the other three factors. Id.