New Delhi, Oct. 7 -- President Donald Trump has threatened to invoke the Insurrection Act, a centuries-old federal law allowing presidents to deploy the military domestically, as legal battles escalate over his attempts to federalise National Guard troops in Democratic-led states. The move has triggered fierce resistance from state officials and renewed debate about executive power and civil unrest in the United States.

President Donald Trump on Monday suggested he might use the Insurrection Act of 1807 to deploy US military forces domestically if federal courts continue to block his orders sending National Guard troops into Democratic-led cities such as Portland and Chicago.

The president's comments came after a federal judge halted hi...