Democrats push for debt ceiling increase amidst looming default date.

House Democrats are preparing a long shot plan to force a vote to raise the debt limit, even if an agreement isn't reached with the Republican majority. The strategy centers on a discharge petition, which requires 218 signatures to force a vote. Democrats are laying the groundwork for such a petition and are working to make sure they have all options at their disposal to avoid a default. The U.S. hit its current debt limit in January, and Treasury Secretary Janet Yellen said in a letter to Congress on Monday that the government could begin defaulting on some of its bills as early as June 1 unless the limit is raised.