Labor unions are divided over vaccine mandates. The split has become more significant after President Joe Biden announced his plan to require federal workers to get inoculated and private companies with more than 100 employees to get them vaccinated. Several prominent unions have praised Biden’s plan. But some unions have pushed back. Police and firefighter unions have fought hard against against mandates in cities. Some federal unions have objected to Biden’s mandate for U.S. government workers. Experts say they are taking different approaches because the labor movement represents workers of all political persuasions.