He can practically taste his new war.
Because having him speak
was intended as theater from the outset, of course.

Hill staff say empty Democratic seats at Netanyahu's speech will be filled by Republican staffers to ensure good visuals, standing ovations
— @dylanotes
The
standing ovations bit is a nice touch, since it implies the Republican chair warmers will be instructed specifically to applaud wildly at whatever the visiting foreign leader says. Again, it all makes for a curious bit of theater; Netanyahu and the Republicans want to sabotage negotiations between the sitting American president and Iran, a move that required working behind the White House's back in the first place. Now that complications have arisen, the Republicans are working to ensure the visual appearance of support for this act of minor sedition by attaching a Potemkin audience—by God, this foreign leader
will receive standing ovations for his dispute with our president.
I have no strong feelings either way on whether Democrats should skip the speech. It would be hilarious to see Netanyahu give a speech to rows full of staffers and interns, but it would be equally karmic to see the churlish leader's reaction to an audience that had the audacity to not applaud his over-the-top pronouncements. House Speaker Boehner seems to make a special point of looking dull-eyed and uninterested when the American president comes to visit; perhaps Joe Biden could rearrange his schedule to come after all, but bring a pillow and a blanket in case he finds Netanyahu's version of events equally dull.
If nothing else, we know that Republicans are insistent not just that the foreign leader will be heard from, but that he will get an approving response even if they have to put ringers in the seats to ensure that. They're quite dedicated to the thought of going to war with Iran—Iraq and Afghanistan didn't get it out of their system, and if anything only made it worse because Iraq and Afghanistan did not go according to neoconservative plans and now they're bitter and pissed off about that—and if it means Benjamin Netanyahu gets to come to Congress and ask them for a declaration of war that their own president won't yet give them, that's what they'll do.