In 1823 American President James Monroe announced that the United States would no longer tolerate European intervention in the Western Hemisphere.
In years to come, America took action against attempts by foreign nations posing threats to the territorial sovereignty and hemispheric interests of the US i.e., Hapsburg Empire’s occupation of Mexico, the Soviet Union placement of missiles in Cuba.
President Trump continued to apply the Monroe Doctrine while in office.
Following a series of terrorist attacks he banned entry to people from a number of countries with poor vetting practices.
He constructed a (nearly completed) wall along the southwest border and forced Mexico to agree to a “stay in Mexico” policy.
President Biden revoked both Trump Executive Orders.
Over one million illegal aliens have crossed the border since Biden took office. Untold numbers have escaped detection.
Despite a record economic downturn and nationwide crime explosion, the Biden administration continues to facilitate, encourage and even entice illegal aliens to come to the United States.
Biden has, de facto, abandoned the Monroe Doctrine.