Gallup Daily tracking for the week ending April 4 finds the two major parties tied at 46% in the congressional voting preferences of registered voters nationally. In the two weeks since Congress passed healthcare reform on March 21, Democrats have tied or trailed the Republicans, after having at least a slight advantage in the weeks prior. Given Republicans’ typical voter turnout advantage in midterm elections, even Republican parity with the Democrats in the candidate preferences of registered voters could translate into significant Republican gains on Election Day.