Actually, what it does is make the Zionist Union more acceptable to a larger group of voters. It solidifies it.
Of course, Netanyahu was attempting to solidify his position, too ... when he announced he was no longer going to permit a Palestinian State to exist ... a remarkable change in his previous stance ... when he said he would go anywhere at any time to form a Palestinian State.
Both sides have announced these things in the last few hours! It looks like both sides are trying to solidify their stance and attract more voters.