WASHINGTON  The Obama administration is holding out for an extension of unemployment assistance and of a variety of expiring tax breaks for low-wage and middle-income workers as part of a deal with Congressional Republicans to extend all the Bush-era tax cuts.

But it is unclear how much leverage the White House has in the tax negotiations, given the drubbing Democrats took in the midterm elections, the tight Congressional calendar and a threat by Senate Republicans to block any legislation until the tax fight is resolved.

In a symbolic nod to President Obama’s pledge to let the tax cuts on upper-income brackets expire on Dec. 31, as scheduled by law, the House on Thursday approved a bill to continue the lower tax rates enacted during the Bush administration for Americans they described as “middle class.” The vote was 234 to 188, with three Republicans joining 231 Democrats in favor; 20 Democrats and 168 Republicans were opposed.

The bill, however, has no chance of passage in the Senate, where even some Democrats say the tax cuts should be extended for everyone, at least temporarily, given the continued weakness in the economy.