Worry about the Aggrandizement of the Executive Branch

How do seemingly healthy societies become affected by disease? Will the United States succumb to this same fate? I’ve repeatedly heard the American denial that our constitution safeguards our society from becoming a Nazi Germany, or a Soviet Russia. The first common perception among Americans is that the Separation of Powers protects us from tyranny because no one branch of government can become too powerful. I’d like to politely point out that the Separation of Powers construct itself was flawed from inception because government cannot logically function free of gridlock when power is equally dispersed between the executive, legislative and judicial branches. Chief Justice John Marshall also aptly recognized this fallacy in 1803 when he declared the judiciary as the ultimate arbiter of constitutional disputes in the Supreme Court case Marbury versus Madison (this concept became known as ‘judicial review’).
The second common perception among many Americans is that states have the power to protect their local citizenry from an overarching federal government. Any claim of a state’s legitimacy as a balance to federal power became erroneous after the Civil War when the Supreme Court decided in Texas versus White that secession was unconstitutional. Without possessing the ability to at least threaten an exit from the United States, states have no real power to challenge the central government (just ask Texas under Obama and California under Trump). Since then, any remaining modicum of states’ rights has been successfully chipped away by the federal government’s assertion of its power of the purse, ability to levy taxes and responsibility to oversee interstate commerce.
Thus, the only meaningful challenge to federal power is the exercise of discretion by the Supreme Court through judicial review. You see, I don’t believe that Congress is a legitimate harness to the overreaching of the executive branch because the legislative branch is too closely tied to the executive branch through the omnipresence of the political parties in the United States. Further, I think it unlikely that the judicial branch of government would decline to exercise the authority it bestowed upon itself in 1803 because judicial review ensures its own survival as a legitimate component of our federal government. However, I pose the question of what would happen if the power of the judiciary was successfully undermined by another branch of government, as would be the case if Congress transferred the power of the legislative and judicial branches to the executive branch, upon a declaration of martial law? The United States of America would become a dictatorship under the executive branch.
We obviously are under martial law, but it’s not hard to appreciate the risk upon a major catastrophe.