Much of the drama has already dissipated; most of these amendments will fail.  The Toomey/Manchin bipartisan compromise appears to be dead in the water, with Sen. Kelly Ayotte (R-NH) and Sen. Heidi Heitkamp (D-ND) pounding home the final legislative nails earlier today. USA Today has a useful primer on what to expect this afternoon and evening, including the items liberals will be watching most carefully:

– The Public Safety and Second Amendment Rights Protection Act (Sen. Joe Manchin, D-W.Va., and three co-sponsors): The compromise background check provision expands background checks to gun shows and Internet sales, but exempts family-to-family and other in-home sales. It also authorizes $400 million to upgrade the national background check database and reduces the turnaround time for background checks from three days to two days; in four years, it would be reduced to one day

– The Assault Weapons Ban (Sen. Dianne Feinstein, D-Calif., and 23 co-sponsors): The amendment bans the sale, transfer and importation of assault rifles, including 157 specifically mentioned in the law — a broader definition than existed from 1994 to 2004. Current lawful owners of assault weapons would be grandfathered.

– The Large-Capacity Magazine Feeding Devices Amendment (Sen. Frank Lautenberg, D-N.J., and 21 co-sponsors): The measure would ban magazines and other devices holding more than 10 rounds, but exempts .22 caliber rifles. Police officers — both on- and off-duty — would also be exempted. It also authorizes federally funded gun buyback programs to purchase high-capacity magazines.

None of those three are expected to pass (see update), though some of the other provisions might.  The assault weapons ban and magazine capacity limit will go down hard, a reality that has forced a beleagured Harry Reid to toss a last-minute gesture of lefty solidarity by backing Feinstein’s doomed dream.   Stay tuned for updates…

UPDATE – Toomey/Manchin fails 54-46, with a handful of aisle-crossers in both directions.  The bill’s supporters were six votes short of 60.  Four Republicans joined most Democrats in voting aye: Toomey, McCain, Kirk and Collins.  Dems going the other way: Baucus, Begich, Heitkamp, Pryor, and Reid (for procedural reasons).

UPDATE II – The primary Republican replacement amendment also goes down, 52-48.  Seven Nine Democrats joined nearly every Republican in voting yes, but it wasn’t enough.  Looks like nothing (or close to it) is getting passed tonight.

UPDATE III – I’m sure this statement won’t be demagogic at all:

White House sets 5:30 pm Rose Garden statement on guns by President Obama

— Jamie Dupree (@jamiedupree) April 17, 2013

UPDATE IV – Here’s the roster of Democrats who joined the GOP on their unsuccessful alternate amendment:

D’s voting for GOP gun bill: Baucus, Begich, Donnelly, Hagan, Heitkamp, Landrieu, McCaskill, Pryor & Tester.

— Chad Pergram (@ChadPergram) April 17, 2013

UPDATE V – Leahy/Collins (re: gun-trafficking) is defeated, 58-42.

UPDATE VI – The difficulty of gun legislation, in one tweet:

RT @hotlinejosh: RT @mikememoli: Asked to explain his vote, Sen. Baucus said one word: “Montana.”

— Lachlan Markay (@lachlan) April 17, 2013

UPDATE VII – Down goes Cornyn’s amendment on concealed-carry reciprocity, 57-43.  That’s an awful lot of votes for the idea, even though it failed.  Chuck Todd points out that more Senators voted to vastly expand gun rights than for the tepid Toomey/Manchin gun control law.  Wow.
UPDATE VIII – Let the lefty machinations begin:
 

—> MT @fschouten it begins: @boldprogressive announces full-page ads against Pryor, Begich, Baucus& Heitkamp over bkgrnd check votes

— Brad Dayspring (@BDayspring) April 17, 2013

UPDATE VII – Surprise:
 

Newtown families, Gabby Giffords at the podium at the White House. whitehouse.gov/live

— Andrew Kaczynski (@BuzzFeedAndrew) April 17, 2013

UPDATE XIII – The federal Assault Weapons Ban stays buried. It wasn’t close: 40 yes votes, 60 no.

UPDATE IX – Great point.  Keep this in mind when you watch the video of President Obama’s furious — and I mean furious — Rose Garden statement:

Didn’t this guy have 60 Democratic votes in the Senate not long ago? Where was the gun-control push then?

— Allahpundit (@allahpundit) April 17, 2013

UPDATE X – The high capacity magazine ban falls 46-54 (majority “no”).  Reid is reportedly pulling the underlying bill.  The Senate will take up two more amendments — which might have a chance — tomorrow.  And that’s all she wrote for tonight.