Related Clues:

• Kill, as a bill
• Prohibit, presidentially
• 86
• Vote down
• Squash
• Nix by Nixon, e.g.
• Presidential rejection
• Power used only three times by George W. Bush
• Pork chop?
• Say no to, as a bill
• Oval Office power
• A certain thumbs down
• Challenge to Congress
• Kill bills
• Line-item item