At a White House press conference Friday afternoon, President Obama said he was “absolutely certain” the Senate amnesty bill would pass the House if it were brought to the floor for a vote. Obama said the Republican leadership should put the bill up for a vote. The problem is, the House doesn’t have the bill. The Senate still has not delivered its bill to the House for consideration.

In the days after the Senate passed its bill, House Ways and Means Chairman David Camp pointed out that the bill is unconstitutional, in its construction. The Senate bill raises revenue by creating new taxes and fees. According to the Constitution, however, legislation that raises revenue can only be introduced first in the House.

This creates a real dilemma for Senate backers of the bill. As my colleague Matt Boyle explained at the time:

When such a revenue-raising bill comes out of the Senate, the Speaker of the House, currently Rep. John Boehner (R-OH), can use a procedure called a “blue slip resolution” to automatically kill it on the grounds that it is unconstitutional. Stockman has been promising to attempt to kill the Senate’s bill that way and, as such, Reid has refused to send it to the House, thereby protecting the bill from being “blue slipped.” The term “blue slip,” Stockman’s office noted in a release, comes from the blue color of the paper on which a resolution is printed that returns a Senate bill back to the Senate in these situations.

This is why supporters of the Senate bill are so eager to conference with the House. They need even a simple piece of legislation on immigration to get around the constitutional problem. Conferees could strip out all the language of the House bill and substitute the Senate provisions, and the resulting bill would be constitutional.

GOP Leadership isn’t blocking the House from voting on the Senate bill. The drafters of the original Senate bill are the ones blocking the House.