WASHINGTON — The US Defense Department’s ambition to use allied factories and shipyards to supplement an overstretched American industrial base in countering China has hit a stumbling block as Japan enters a period of political uncertainty following Sunday’s general election.

On Tuesday, the Pentagon released the first of what is intended to be annual implementation plans for the National Defense Industrial Strategy, highlighting the need to address key challenges to the US defense industrial base and warning of the risks of inaction.