Veto override

So why was the POTUS so adamant about blocking the bill that would allow 9/11 families to sue foreign governments for state sponsored terrorism that kills or injures American citizens ? .....and no....it's not because he fears it puts our troops in jeopardy like he says.....that's downright laughable to suggest he has sleepless nights worrying about our troops.......my guess is that the President who has used 10 times as many drone strikes as any other President..... Drone strikes that have killed many innocent bystanders.... drone strikes that have killed even U.S. citizens that were fighting with ISIS...... maybe POTUS is worrying about his legacy if lawsuits start rolling in for the next 10 years as the families of the people his drone strikes killed start suing the U.S. Government........that could put a damper on his Nobel Peace prize.