> President is Executive branch of government, therefore can pass a new law just by signing it without approval of Congress. The executive branch of government executes laws, it does not (and Constitutionally cannot) create them. Executive orders are valid to the extent that they direct actions within the executive branch within the laws binding that branch and apply only powers the President has under the Constitution and laws.

The practical distinction may vanish when the other branches do not effectively check the executive when it exceeds its Constitutional power, but that's not inherent in the President heading the Executive branch -- the same is equally true of excesses in other branches, though the unitary nature of the executive provides less of an intra-branch check on abuses by the President than exists for any actor in the legislative or judicial branches (though collective excesses, such as -- as a purely hypothetical example -- the Supreme Court intruding into Congress' Constitutional role in judging the propriety of Presidential electoral votes including the process by which they are assigned -- can still occur and be problematic if left unchecked by the other branches.)