Nikki Haley, Gov. Chris Sununu, Sen. Chris Van Hollen

Former U.N. ambassador and Republican presidential candidate Nikki Haley sat down alongside New Hampshire Gov. Chris Sununu to tout his endorsement of her in a joint interview with ABC "This Week" co-anchor Jonathan Karl. Democratic Sen. Chris Van Hollen on Sunday said the Biden administration is not being heeded in its entreaties for Israel to reduce the civilian death toll from the military campaign against Hamas extremists in Gaza, which is being carried out with U.S. support.