On Friday, President Trump issued his first veto following an attempt by Congress to block his emergency declaration. His second veto is likely close behind.

Although Thursday’s Senate vote rebuking Trump for seizing emergency powers to build a wall at the southern border drew most of the attention, it was the second Senate rebuke directed at Trump’s policy this week. The first came on Wednesday when the Senate passed a resolution to end U.S. military support for the Saudi-led war in Yemen and limit the president’s power to engage in the conflict without Congressional approval.

As that bill is all but certain to pass the House, it’s headed for Trump’s desk, too.

Trump has repeatedly stood by his administration’s wavering response to the killing of U.S. resident and journalist Jamal Khashoggi. He has defended the Saudi Crown Prince implicated in the killing and refused to back down on U.S. support for the Saudi-led coalition waging a brutal war in Yemen. He is hardly going to put his signature on such a bill.

Trump is also unlikely to support the bill as it invokes the 1973 War Powers Act to curtail his power to call the shots on U.S. engagement in Yemen. That measure allows Congress to pull U.S. troops from an undeclared conflict and set limits on what actions can be taken without Congressional approval thus directly challenging his power.

Indeed, the White House House made its disapproval of the resolution clear issuing a statement, as reported by Defense News, contending that the resolution “seeks to override the President’s determination as Commander in Chief" all but promising a veto.

But, as the White House closely guards its power by wielding such vetoes, Congress must not back away from pressuring Trump on abuses of power. Instead, those vetoes should be a clear warning to the Republicans who have so far refused to vote against Trump that he has no intention of doing anything other than using the full extent of his powers as president to enact his will, even when it means circumventing Congress's rightful authority.