WASHINGTON — President Obama will soon accelerate his efforts to put a lasting imprint on the country’s judiciary by simultaneously nominating three judges to an important federal court, a move that is certain to unleash fierce Republican opposition and could rekindle a broader partisan struggle over Senate rules. In trying to fill the three vacancies on the 11-member United States Court of Appeals for the District of Columbia Circuit at once, Mr. Obama will be adopting a more aggressive nomination strategy. He will effectively be daring Republicans to find specific ground to filibuster all the nominees. White House officials declined...