Sobran is wrong: there were never three safeguards.
There was and is only one safeguard: that the general population of the U.S. behave in a manner conducive to the existence of a free society.
Only then can the elected leaders be expected to act in the best interests of the country, in accordance with the Constitution.
At the same time, the electorate is expected to hold their representatives accountable, and to protect their own rights, as well as the rights of others.
And finally, all people are expected to recognize and follow through upon their duties to society.
Sobran is engaged in a bit of Constitutional idolatry here. He expects that somehow a scrap of paper can act as a hedge against people who want to get around the constraints it embodies. Without the underlying moral concensus that created it, the Constitution is without meaning.
To understand what's going on, one has got to go back to moral first principles. In fact, one is pretty much required to go back to Christian first principles.
If Mr. Sobran is so wrong, and rather doubt that he is, maybe you should tell him about his careless writing-I only brought it to the attention of more people. His web site invites reply.