The Democrat-controlled Senate approved its first budget blueprint in four years early Saturday, a political milestone that capped months of GOP criticism and set the stage for direct negotiations with the Republican-controlled House.The Senate blueprint calls for nearly $1 trillion in new taxes over the next decade and only modest reductions in projected government spending. While it would replace sharp, automatic spending cuts known as the sequester, it would do little to alter the nation’s financial outlook, permitting the portion of the national debt held by outside investors to swell from nearly $12 trillion today to more than $18 trillion by 2023.House Republicans, by contrast, have adopted an anti-tax spending plan that would balance by 2023, leaving the national debt to top out at about $14 trillion. But the House budget, drafted by Rep. Paul Ryan (R-Wis.), calls for a radical reduction in the size of government by curtailing spending on dozens of programs for the poor, repealing President Obama’s health-care law and partially privatizing Medicare for people now younger than 55.Neither of the budget plans will ever be put into effect. Instead, they set the extreme boundaries as Washington prepares to open a new chapter in the long-running debate over taxes and spending.In the coming days, Senate leaders plan to request a formal conference on the budget with the House. That would establish Ryan, the former vice-presidential nominee who chairs the House Budget Committee, and Senate Budget Committee Chairman Patty Murray (D-Wash.) as lead negotiators for their respective parties heading into another potential showdown later this summer over the federal debt limit.