WASHINGTON – A bipartisan measure limiting President Donald Trump's authority to launch military operations against Iran is moving toward approval in the Senate. The resolution, authored by Democratic Sen. Tim Kaine of Virginia, asserts that Trump must win approval from Congress before engaging in further military action against Iran. Eight Republicans sided with Democrats Wednesday on a procedural motion to force a vote on the issue as soon as Thursday. Kaine and other supporters said the resolution was not about Trump or even the presidency, but instead was an important reassertion of congressional power to declare war. Answering a claim by some of Trump's supporters – and Trump himself – that the measure sends a signal of weakness to Iran and other potential adversaries, Kaine said the opposite was true. "When we stand up for the rule of law – in a world that hungers for more rule of law – and say ‘this decision is fundamental, and we have rules that we are going to follow so we can make a good decision,’ that's a message of strength,'' Kaine said Wednesday. Republican Sen.