由于《第42条法案》终止，之前被搁置一旁的美墨边境移民再次成为棘手问题。请看本报昨日的评论：

The recent expiration of Title 42 application to U.S. immigration processing protocols along the U.S.-Mexico border has put into the limelight a problem previously on the back burner. Starting from May 12, the COVID-19 pandemic-era policy that allowed for the rapid expulsion of migrants seeking asylum is no longer valid.

报道中的on the back burner就是“因为不紧急或者不重要而搁置一旁”。