Well, if someone could prove that, things would be different.
The Constitution proves it with the Twentieth Amendment, Section Three and the first two words of the eligibility requirements in Article II.
The Twentieth Amendment is an instruction to Congress to ensure that the President-Elect is eligible to serve, in fact he is burdened with providing proof to Congress, and if there is a failure to qualify, Congress is instructed to name a President. Congress, in this instance, as they are prone to do all of the time, simply ignored their Constitutional duty. That they ignored their duty does not mean we had a legal president because the first two words of the eligibility requirements plainly state “No person” who is a natural born citizen can serve as President. It doesn’t say “No Person except those not vetted by Congress”. It says “No person”. That Congress failed it’s Constitutional duty under the Twentieth Amendment, Section Three does not a legal President make. It makes a usurper. No matter what the media, democrats, and rinos call him, Obama was an eight year userpation of the office of President.