A federal appeals court has ordered the Trump administration to halt aboveground construction of its proposed $400 million, 90,000-square-foot White House ballroom, ruling that the president cannot move forward with the massive project without authorization from Congress. The court made an important point: whether the ballroom itself is a good idea isn't the issue. The issue is whether a president can unilaterally undertake such an enormous transformation of one of America's most important public buildings without following the constitutional process. The court's answer was clear—Congress has a role, and the executive branch cannot simply bypass it. Our system of checks and balances exists for exactly this reason. Presidents have significant power, but that power has limits. Requiring the administration to seek congressional authorization protects the separation of powers and reinforces the principle that no president gets to make the rules alone. The White House is a national landmark that has stood through generations of presidents. Major changes to it deserve transparency, oversight, and respect for the laws governing our public institutions. Add your name to celebrate the appeals court for defending checks and balances, protecting congressional authority, and reminding Donald Trump that even the president must follow the law.