<span>I think he probably meant that the Constitution is not to be set in stone and should change to fit the times, which is my the Founding Fathers put in the Amendment process.
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"A constitutional door is left open" refers to the question of whether an action is constitutional or unconstitutional. There is gray area that needs to be discussed.
As head of a political party<span> the </span>president<span> uses his power and prestige to support party goals or candidates.</span>
