Read the law. It's law passed by Congress giving the POTUS the authority to unilaterally forbid immigrants/invaders entry into America.
8 U.S.C. s 1152(a)(1)
From the above: "Whenever the President finds that the entry of any aliens or of any class of aliens into the United States would be detrimental to the interests of the United States, he may by proclamation, and for such period as he shall deem necessary, suspend the entry of all aliens or any class of aliens as immigrants or nonimmigrants, or impose on the entry of aliens any restrictions he may deem to be appropriate."
Congress gave the President the power to forbid entry into the USA of any immigrant according to the above law.
He also has the power to order troops to the border, as he has done. He has already ordered troops to the border, but only in a impotent capacity. If he can order ten soldiers, he can order 10,000 soldiers. If he can order 10,000 soldiers, he can order them to be armed and have some teeth. He just has to do it. He can prevent anymore incursions onto American soil. If he'll just do it.
The fed judge hacks have countermanded some things, but they cannot stop him from performing the above.
Meanwhile, millions, MILLIONS of these crimigrants are coming across our border.
But, bushbots like you, er, trumpbots like you are deliberately obtuse and can't be bothered with anything so mundane as actual research.
In one of the great ironies of life, one of the Congress vs. Trump cases is going before the DC appeals court headed by Judge Merritt Garland. Yes, that Merritt Garland, the very one that Republicans blocked from being on the Supreme Court. I wonder if he will vote the same way that McCain did after Trump called him a coward for being a prisoner of war.
With ROEs to turn their weapons over to any other than US military they may encounter at the border.
Very important part here. The military is being used as window dressing and chair weights. They need to be turned loose to conduct full scale military actions as required to secure our border.
Until that happens, I will just sit back and chuckle every time someone mentions military on the border.