The president cannot pass laws without Congress, and Congress cannot pass laws without Presidential approval. Though the presidential veto is a formidable power, the ability of Congress to override it ensures that the president does not have full authority over what becomes law and what does not. read more
The president's power is limited by a system of checks and balances written into the United States Constitution. The legislative and judicial branches have specific power to deny or impede the executive branch's actions. read more
The war power act was enacted to limit the presidential power to act against congressional will, basically as a rouge president, which has really come about since WWII. Congress, even prior to the war powers act, has the power to formally declare war and fund wars. read more