How does the structure of the federal court system ensure that americans have ample opportunities to seek justice?

For starters, if you believe that a court has wronged you, you can seek justice from courts of appeal that revise the decision to make sure that it was properly made. If you still think that they've wronged you after that, you can ask for the help of the supreme court which checks whether it was constitutional what they did. There are many steps that you can undertake.

The answer is william henry harrison pursued and defeated british forces retreating into canada.