Well, Senator Cornyn, let’s hop in my way-back machine and start from the beginning.
Senator Cornyn apparently doesn’t know the Constitution, as well as Barack Obama, knows it.
The Congress shall have the power…To establish an uniform Rule of Naturalization … throughout the United States U.S. Constitution, Article I, Section 8
Article II governing the Executive Branch of federal government does not authorize the president to promulgate immigration policies. Ever. The president has only authority to execute laws enacted by Congress.
…he [the president] shall take Care that the Laws be faithfully executed…U.S. Constitution, Article II, Section 3
Responding in October 2010 to demands that he implement immigration reforms unilaterally, Obama declared, “I am not king. I can’t do these things just by myself.” In March 2011, he said that with “respect to the notion that I can just suspend deportations through executive order, that’s just not the case.” In May 2011, he acknowledged that he couldn’t “just bypass Congress and change the (immigration) law myself. … That’s not how a democracy works.” [Source: The Heritage Foundation]
Despite the fact Obama knew he lacked authority to create immigration policies out of thin air, he did so in 2012 with his DACA executive order. Adding injury to insult, three federal judges ruled President Trump’s cancellation of DACA “unconstitutional”, a classic example of judges creating law out of thin air.
President Trump does not say DACA should not be the law; he simply places responsibility for crafting immigration policies in the lap of Congress.
Senator Cornyn, mostly a good guy, definitely Texan in speech and outlook, is a poster child for repeal of the Seventeenth Amendment.