After fierce political lines were drawn over mask-wearing, President Joe Biden is bracing for backlash ahead of an expected mandate for federal government workers to be vaccinated against the novel coronavirus.

Biden’s announcement, anticipated to cover both federal employees and contractors, promises to inflame passions amid a spike in delta variant COVID-19 cases. It also imperils the standing of the president and his party before the 2022 midterm elections after polls awarded them top marks for their handling of the pandemic.