Withdrawing from the Paris Climate Accord and the Iran Nuclear Deal

In an interview in the Frankfurter Allgemeine Sonntagszeitung weekly, German Chancellor Angela Merkel said:

“America is and remains the superpower, but at the moment it doesn’t recognize multilateral agreements in all areas, as shown by the decision to leave the [Paris] climate accord and now the tariffs that President Trump has levied against Europe.”

I would agree with Chancellor Merkel with respect to the tariffs that the Trump administration has levied (or is threatening to levy, I am not sure which it is) against Europe (and other places).  However, when it comes to the Paris climate accord, and similarly the Iran nuclear agreement, I think Chancellor Merkel is missing an important point regarding the American system.

When Chancellor Merkel signed the Paris climate agreement, the agreement was approved by both houses of the German parliament, the Bundestag (the lower house) and the Bundesrat (the upper house).  Not so in the United States.  While President Barack Obama signed the agreement on behalf of the United States, he neither submitted it to the Senate for ratification as a treaty nor asked Congress to pass a law approving it.¹  Unlike Chancellor Merkel, President Obama just signed it, which meant President Donald Trump didn’t need Congress’s approval to withdraw from the agreement.  President Obama took us in on his own; President Trump took us out on his own.²

It is a little unfair of Chancellor Merkel to complain about the United States not recognizing multilateral agreements that the United States government, as opposed to just its president, never approved.  But it does show the problem with building your presidential legacy on the sand of executive orders and agreements as opposed to the rock of Congressionally approved treaties and laws.
-----------
¹ I am not sure the latter would have been the proper way to do it, as opposed to the former.  In any case, I assume he didn’t send it to Congress, either way, because he did not think it would have been approved.
² The same was true of the Iran nuclear deal.