US troops arrive in France, 1917

The transcript describes the unexpected and timely arrival of American forces, overcoming submarine threats. The people welcome them, recognizing their strength and wealth. This arrival is seen as crucial for the allies' success, potentially saving them if they hold out until the Americans join the lines.

What does the phrase 'Just in the thick of time' imply about the timing of the Americans' arrival?

What is suggested about the fate of the allies if they hold out until the Americans enter?