WASHINGTON -- Senate Democrats unveiled their first budget plan in nearly four years Wednesday, a proposal that sets up a lengthy fight with Republicans over the two parties' differences on taxes, spending and Medicare.The Democratic plan, which Republicans instantly criticized, would reduce deficits by $1.85 trillion over 10 years and would replace the recent automatic spending cuts, called the sequester, with higher taxes and a different spending-reduction plan.The struggle over ways to reduce the nation's $16.7 trillion debt, and the trillions likely to accumulate in the future, dominated talk and debate all over Capitol Hill.At the Capitol, President Barack Obama met with House Republicans. Upstairs, senators were rejecting, 52-45, a Republican bid to take away funding for Obama's healthcare plan, at least the 34th time that Congress has tried to end it.In a nearby office building, Republican budget writers began crafting a 10-year deficit reduction plan that Democrats disliked.The Democratic-run Senate Budget Committee was countering with its own blueprint.Obama's session with House Republicans was seen as the most crucial of his four meetings this week with congressional caucuses. Republicans have run the House since 2011, and many were elected by expressing opposition to his fiscal and healthcare policies.House Speaker John Boehner, R-Ohio, described the meeting as "a frank and candid exchange of ideas."But, he warned, "there are some very real differences between our two parties, like issues: jobs, balancing the budget and what do we do to get our economy moving again. Republicans want to balance the budget. The president doesn't. Republicans want to solve our long-term debt problem. The president doesn't."In the Senate, Democrats began a renewed push for a budget after balking at such action for years.They'd been concerned that such a plan would become valuable ammunition for Republicans in the 2010 and 2012 elections.Budget plans are supposed to be road maps for the legislation that sets spending for government agencies and programs.