[311] After lower courts partially blocked the new restrictions, the Supreme Court allowed the September version to go into full effect on December 4, 2017,[312] and ultimately upheld the travel ban in a June 2019 ruling.[313]

Family separation at border
Main article: Trump administration family separation policy
.mw-parser-output .tmulti .multiimageinner{display:flex;flex-direction:column}.mw-parser-output .tmulti .trow{display:flex;flex-direction:row;clear:left;flex-wrap:wrap;width:100%;box-sizing:border-box}.mw-parser-output .tmulti .tsingle{margin:1px;float:left}.mw-parser-output .tmulti .theader{clear:both;font-weight:bold;text-align:center;align-self:center;background-color:transparent;width:100%}.mw-parser-output .tmulti .thumbcaption{background-color:transparent}.mw-parser-output .tmulti .text-align-left{text-align:left}.mw-parser-output .tmulti .text-align-right{text-align:right}.mw-parser-output .tmulti .text-align-center{text-align:center}@media all and (max-width:720px){.mw-parser-output .tmulti .thumbinner{width:100%!important;box-sizing:border-box;max-width:none!important;align-items:center}.mw-parser-output .tmulti .trow{justify-content:center}.mw-parser-output .tmulti .tsingle{float:none!important;max-width:100%!important;box-sizing:border-box;text-align:center}.mw-parser-output .tmulti .tsingle .thumbcaption{text-align:left}.mw-parser-output .tmulti .trow>.thumbcaption{text-align:center}}Children sitting within a wire mesh compartment in the Ursula detention facility in McAllen, Texas, June 2018
The Trump administration separated more than 5,400 children of migrant families from their parents at the U.S.–Mexico border while attempting to enter the U.S, a sharp increase in the number of family separations at the border starting from the summer of 2017.[314][315] In April 2018, the Trump administration announced a "zero tolerance" policy whereby every adult suspected of illegal entry would be criminally prosecuted.[316] This resulted in family separations, as the migrant adults were put in criminal detention for prosecution, while their children were separated as unaccompanied alien minors.[317] Administration officials described the policy as a way to deter illegal immigration.