WASHINGTON, Jan 19 (Reuters) - U.S. President Joe Biden on Wednesday accused Republicans of blocking his legislative agenda for political purposes, saying the party is more interested in defeating his presidency than doing things for the American people. During a news briefing marking the one-year anniversary of his presidency, Biden said he did not overpromise on his agenda, but did underestimate Republican opposition. "I did not anticipate that there would be such a stalwart effort to make sure that the most important effort was to make sure President Biden didn"t get anything done," he said. Biden added: "Name me one thing they"re for."