1. The IRS isn&#x27;t signing binding international agreements, they&#x27;re agreeing to cooperate with foreign governments in the reporting of financial assets, which is well within their legal privilege.<p>2. The fourth amendment doesn&#x27;t apply to data you&#x27;re legally compelled to surrender to the government. By your logic, every form 1040 that&#x27;s ever been filed is a fourth amendment violation.<p>3. The eighth amendment has almost never been used in a constitutional case involving excessive fines. When it has, the court has primarily used it to prevent pseudo-fines that aren&#x27;t really called fines in order to skirt the eighth amendment.<p>Sure, FATCA might be annoying, but a legal challenge has almost nothing going for it. Don&#x27;t get your hopes up.