Israel has already taken steps that will directly empower Hamas. Netanyahu’s knee-jerk statements in response to the Cairo agreement, along with the unilateral decision of the minister of finance to withhold tax transfers to the PA will feed the extremists. The taxes collected by Israel (by agreement) do not belong to Israel. This is Palestinian money, and without it, the PA will go bankrupt. The PA will begin to collect taxes in Gaza, but with the high unemployment there, the tax base is quite low.
If the US and other Quartet members also freeze donations to the PA, the economic successes which have paved the road of stabilization will collapse. All the achievements of the past several years will fade, replaced by a new round of violence.