—we emphasized that protection from lost testimony generally falls solely within the ambit of the statute of limitations.

It is not enough that lost evidence or testimony be of some benefit to an accused; to make the requisite non-speculative demonstration, a defendant must show that the loss "has actually impaired his ability meaningfully to defend himself."

This court held that the impeachment value of the state conviction was "not the type of prejudice that due process principles seek to prevent."

The mere assertion of a missing witness's potential usefulness does not show the actual prejudice required

Ninth Circuit case law teaches that the clock does not begin to run for purposes of pre-indictment delay until the final criminal act (or final overt act in the case of a conspiracy) is allegedly committed.

The government is otherwise under no duty to file charges as soon as probable cause exists or even when there is enough evidence to establish guilt beyond a reasonable doubt.

Other circuits have adopted more of a balancing approach, weighing three factors-the length of the delay, actual prejudice to the def6ndant resulting from the delay and the government's reason for the delay.