A court in Venezuela has upheld long prison sentences for six American oil executives detained in the South American country on corruption charges for more than four years. Venezuela’s supreme court announced the ruling late Friday, disappointing family members who had hoped the surprise decision last fall to hear the appeal, and by a top State Department official, signified Nicolás Maduro’s regime was looking to release the men as part of a gesture to engage the Biden administration in talks over U.S. sanctions. The court didn’t provide any information on its decision, and the order itself was not immediately available. Venezuela’s judicial system is stacked with pro-Maduro officials who routinely issue decrees in accordance with Maduro’s viewpoints. The men known as the Citgo 6—for the Houston oil company where they worked—were lured to Caracas around Thanksgiving in 2017 to attend a meeting at the headquarters of Citgo’s parent, state-run oil …