By James Oliphant (Reuters) – Donald Trump is looking to seal the deal. Three other Republicans are hoping to slow his march toward the Republican nomination. That’s the set-up for Monday’s Iowa caucuses, the first nominating contest of the 2024 election. For Trump’s top rivals, Florida Governor Ron DeSantis and former UN ambassador Nikki Haley, the caucuses will be a test of their continued viability as candidates. The pressure is on DeSantis, who has made a strong finish in Iowa his top priority. The caucuses not only provide an early snapshot of how voters view the presidential field but ca…