The correct option is E It set the tone for U.S. foreign policy in the future.
The effect of the Monroe Doctrine on world politics is best describes as it set the tone for U.S. foreign policy in the future. It started by setting forth principles that were meant to be immutable.
And over time, it showed how they can be changed in response to
changing circumstances — such critical facts as its political stability,
the growth of the economy, and its military readiness.