For the past 18 years, the Palestinian Authority has honored Palestinian terrorists serving criminal sentences in Israeli prisons and rewarded the families of those “martyred” by their own violent acts.This comes as no surprise to Israelis, who have both suffered the attacks of terrorists for decades and watched as the terrorists themselves were honored with official salaries or buried as patriotic heroes.But it is a surprise to American officials.Even after two decades of PA support for terrorism, the Obama administration continues to ignore it or even make excuses for these payments.A recent State Department publication dismissed the payments as “an effort to reintegrate [released prisoners] into society and prevent recruitment by hostile political factions.” Even in the unlikely event leaders at the US State Department actually believe this, they would have to explain why these “social welfare” payments increase dramatically with the severity of the crime for which the terrorist is convicted.Where else in the world does a prisoner receive benefits that actually increase with the level of violence committed? For the many Americans who have only recently become familiar with this heinous practice, the shock is even greater that American taxpayer dollars have been used to make these payments to terrorists. As a US senator and a custodian of our citizens’ resources, I find this practice reprehensible.Since 1998 when this terrorist payments program reportedly first began, the United States has contributed more than $4.6 billion (in constant dollars) to the PA . The great majority of this amount has been in straight budgetary support to the PA , enabling it to meet its budgetary commitments. That includes payments to terrorists and the families of “martyrs.”It is difficult from the outside to determine how much has been spent rewarding terrorists over that period, although the budget number for the payments program in recent years has been about $128m.annually. Also, the 2014 PA budget included a separate line item for the “Institution for the Care of Martyrs’ Families” that totaled $155m. Together, these amounts would be 86 percent of the $327.6m. requested this year by the Obama administration for bilateral assistance to the PA .For the past two years, I have been working with my Senate colleagues to reduce the amount of aid to the PA by the amount that is paid out to terrorists and their families.When legislation first took effect with that purpose, PA President Mahmoud Abbas tried to avoid such consequences by transferring the program to the PLO .To put an end to that shell game too, this year we are amending the annual appropriations act accordingly. Our hope is that, by restricting our voluntary assistance to the PA and applying this budgetary pressure, it will end this immoral program of rewarding and encouraging terrorists.I do understand that some are reluctant to impose more pressure on a financially weak and dependent PA , believing that it would deprive President Abbas of what little remains of his authority and status as a negotiating partner, thus making a negotiated settlement even less likely. Even some Israeli officials have tried to avoid steps that could weaken the PA ’s stability as a West Bank security provider.But such cold calculations of cause and effect can only follow a firm stand on moral principle. The Palestinian Authority does not deserve immunity just because of its fragility. These payments provide rewards and motivations for brutal terrorists, plain and simple. To provide US taxpayer money to Abbas and his government so that they can treat terrorists as heroes or glorious martyrs is morally unacceptable. To tolerate such an outrage because of concern for Abbas’s political future or preserving the PA ’s security role amounts to self-imposed extortion.If the PA ’s fragile financial condition requires US assistance, then it is their policy – not ours – that needs to change.The author is a US senator (R-Indiana), and a member of the Senate Intelligence Committee.