DES MOINES — The top Democratic presidential candidates sparred on Tuesday with leaders of the Iowa Democratic Party, and at times with one another, in a strenuous effort to shape the terms and timing of the release of results from the presidential caucuses here. Fault lines that emerged between the campaigns on Monday night quickly deepened on Tuesday, as several campaigns pressed the state party for a speedy and full release of the results and representatives of former Vice President Joseph R. Biden Jr. continued to criticize the legitimacy of the process. The state party said in a midday statement...