Not because he is wrong (though he is) but because he is incompetent. He has embarrassed the nation by stupidly offering military support to our best ally that he should have known he could not deliver.
He should have sought Labour's support before ever recalling Parliament. When refused that support, he already had his answer (as his Whips could have told him) without this debacle. He could have politely and discreetly informed President Obama.
He has lost the trust of many of his own MPs, who are briefing the press that they are "unwilling to take him at his word". Since his word is given and retracted regularly in the face of mere opinion polls, let alone parliamentary defeats, who can blame them?
The man is a lightweight unworthy of his office - or any position of responsibilty. There should be no portrait on the Downing Street stairs, no pension and no peerage. He should just go quietly and let us begin to forget him.