Why is it unconstitutional? Does the Constitution claim that foreign governments have the right to buy any US asset they want?
"Does the Constitution claim that foreign governments have the right to buy any US asset they want?"
No. And Washington, Jefferson, Henry, Madison, etc would almost assuredly, from what I know from reading history, have frowned on this Dubai deal thing, that many conservatives for some reason blindly support.
So Congress put itself in the bizarre position of passing a bill that prohibits this foreign company from having any operating agreements with U.S. ports -- despite the fact that countries like China and Saudi Arabia have operated ports in the U.S. for years.
A law like this that is aimed at restricting a specific entity is known as a "bill of attainder," and is explicitly prohibited under Article I, Sections 9 and 10 of the U.S. Constitution.
"Bills of attainder, ex post facto laws, and laws impairing the obligations of contracts, are contrary to the first principles of the social compact, and to every principle of sound legislation. ... The sober people of America are weary of the fluctuating policy which has directed the public councils. They have seen with regret and indignation that sudden changes and legislative interferences, in cases affecting personal rights, become jobs in the hands of enterprising and influential speculators, and snares to the more-industrious and less-informed part of the community." -- James Madison, Federalist Number 44, 1788
Good heavens -- I can't imagine what James Madison would think of what has become of our U.S. Congress these days.
"Why is it unconstitutional? Does the Constitution claim that foreign governments have the right to buy any US asset they want?"
Since when is a BRITISH company a U.S. asset?