Nurses and health care workers across the country are finding strength in numbers and with labor actions not seen in years. In California, which has a strong union tradition, Kaiser Permanente management misjudged workplace tensions during the covid-19 crisis and risked a walkout of thousands when union nurses balked at signing a four-year contract that would have slashed pay for new hires. In Colorado, Pennsylvania, North Carolina and Massachusetts, nurses have been embroiled in union battles over staffing and work conditions. As deadly coronavirus cases spiked this year, daily pressures intensified on hospital floors. Some nurses retired; some became travel nurses, hired by agencies that advertised more than double, even triple, the day rates for intensive care unit, telemetry and emergency room nurses. Others gave up their jobs to avoid possibly carrying the covid virus home to their families. “Things had gotten particularly stark for nurses,” said Rebecca Kolins Givan, …