Most gag orders can be challenged and have to serve a benefit of some kind and be of limited duration (like to guarantee a fair trail).<p>A NSL gag order can be challenged.<p><i>In December 2008, the Second Circuit Court of Appeals ruled that some of the NSL gag provisions were unconstitutional, in part because they limited judicial review of the gag orders and forced courts to defer to the government’s assertions about the necessity of a gag order and also thwarted the ability of recipients to challenge a gag order.</i><p>[source:] <a href="http:&#x2F;&#x2F;www.wired.com&#x2F;2010&#x2F;08&#x2F;nsl-gag-order-lifted&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.wired.com&#x2F;2010&#x2F;08&#x2F;nsl-gag-order-lifted&#x2F;</a><p>And more gag provisions were overturned in 2013.<p><a href="https:&#x2F;&#x2F;www.crowelldatalaw.com&#x2F;2013&#x2F;04&#x2F;gagging-the-fbi-the-unconstitutionality-of-national-security-letters&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.crowelldatalaw.com&#x2F;2013&#x2F;04&#x2F;gagging-the-fbi-the-u...</a><p>I think the overturning of these provisions of the NSL gag order she the power of the 1st Amendment a show the US judiciary tend to be skeptical whenever the government attempts to limit free speech.