I asked Pat Toomey, President of the Club for Growth, for a comment about this story. 

According to Toomey:

Huckabee is great at making pledges, but he is also great at breaking them.  In 2001, he told Arkansas “Taxes are out” but then proceeded to support higher taxes repeatedly throughout the rest of his tenure as governor.   In light of his record, taxpayers have good reason to doubt his Johnny-come-lately pledges on the presidential campaign trail.