<h1>National Guard deployment to Illinois faces limits pending review, with Insurrection Act invoked but its applicability questioned.</h1> The legal issue centers on whether the Insurrection Act permits use of federally controlled National Guard troops to protect federal property or perform patrols absent a showing that civil authority has failed; courts noted lack of substantial evidence of such failure, citing arrests, functioning courts and active federal enforcement, and accordingly limited operational use while leaving federal control in place pending further proceedings.