WASHINGTON (Reuters) -Republican U.S. House Speaker Mike Johnson on Wednesday cast doubt on a bipartisan effort to tighten border security, saying Democratic President Joe Biden does not need new laws to tackle the problem, signaling that a compromise being negotiated faces long odds of passage. In his first formal speech since taking the speaker's gavel in October, Johnson said a deal taking shape in the Senate does not go far enough to prevent migrants from entering the country along the U.S.-Mexico border. "From what we've heard, this so-called deal does not include transfo...