[Non-Sequitur]

He is a citizen, but not a natural born citizen and could not run for POTUS.

And what clause in the Constitution states that?

[Danae]

Article 2 Section 2: “No person except a natural born citizen, or a citizen of the United States, at the time of the adoption of this Constitution, shall be eligible to the office of President; neither shall any person be eligible to that office who shall not have attained to the age of thirty five years, and been fourteen Years a resident within the United States.”

[Lower55]

“
He is a citizen, but not a natural born citizen and could not run for POTUS.
And what clause in the Constitution states that?”

The one that states that a President has to be Natural Born. He (Obama) is not a NBC.