US congressional leaders accomplished a key goal this week, when both the House and Senate completed work on their own versions of a 2006 budget, sending lawmakers home for an extended Easter holiday.

But the $2,600bn (£1,350bn, €1,950bn) budgets they left behind reveal sharp differences of opinion over tax cuts, spending plans, and most important, deficit reduction. The rifts guarantee a difficult negotiation when they return next month, and threaten to derail the budget.