Labor rights activists celebrated the House passage of a new bill Thursday they say is a major step forward in ensuring workers’ rights and promoting a more sustainable economy. The Protecting the Right to Organize Act, or PRO Act, would strengthen unions’ bargaining power and defend the right to strike; penalize companies that go after workers who organize; and weaken so-called right-to-work laws that allow workers to opt out of paying dues to unions. The bill is expected to face stiff resistance in the Republican-controlled Senate.