* How angry are Republicans at Harry Reid? So much they’re willing to filibuster a bill with a bunch of tax breaks they support, to protest his refusal to allow amendments:

Republicans blocked the measure, even though many support the slew of expired tax breaks, out of frustration with Reid, whom they say is preventing the minority party from offering amendments to the bill.

“We have a tax bill here that members from both sides want to improve and support. Yet we don’t get a chance to amend it,” Senate Minority Leader Mitch McConnell (R-Ky.) said ahead of the vote. “[Democrats] have turned the Senate into a graveyard of good ideas and good democratic debate.”

Mitch McConnell, of course, has played no role whatsoever in grinding the Senate to a halt and only wants the Upper Chamber to function as well as possible.

* Norm Ornstein has an excellent and comprehensive piece reminding us of the degree to which the filibuster remains a serious problem in the Senate, though people have moved on from the topic. The latest victim: a bipartisan bill on energy efficiency that had majority support, but couldn’t defeat a GOP filibuster.

* Speaking of which: Yesterday we told you that Scott Brown lobbied his colleagues to filibuster it, so as to prevent his opponent, Sen. Jeanne Shaheen, from getting a legislative victory. Today, Shaheen’s New Hampshire colleague Kelly Ayotte, a Republican, said she voted against the filibuster despite being lobbied by Brown:

“I just did what I thought was best based on my state and voted the way I thought I should,” Ayotte told The Huffington Post.

That would seem to mean she doesn’t think Brown was doing what was right for the state, right?

* Mitch McConnell’s longtime political mentor in Kentucky is breaking with the Senate Minority Leader over the latter’s adamant insistence on repealing Obamacare, because — imagine this — he recognizes that the law is helping lots of people in his state:

“For Mitch McConnell to decide the new health program is not good for Kentucky—it tells me he’s not looking out for his own constituency,” he says.

Reminder: McConnell would repeal Kentucky Kynect, which has already signed up over 400,000 of his constituents for health coverage. — gs

* The White House is working very hard behind the scenes to keep Senate Democrats from breaking with the judicial nomination of David Barron, who wrote the memos authorizing the drone strike on an American citizen-turned-Al Qaeda operative. Democrats may not be comfortable about that memo being kept secret, but the fact that they’re getting to see it probably ensures Barron’s confirmation.

* Republicans may be dismissive of Harry Reid’s push to amend the Constitution to allow for regulation of campaigns, but Senate Judiciary Committee chairman Pat Leahy is taking it seriously. He’ll be holding hearings on it in June.

* Good reporting from Pro Publica, which analyzed Medicare payment data and found that 1,800 doctors billed the program for the most complex and expensive kind of office visits over 90 percent of the time, despite the fact that nationally, only 4 percent of office visits are billed at that rate.

* The Federal Communications Commission voted to move ahead with a plan that would allow internet service providers to create a slow lane and a fast lane to your computer, based on which web sites are willing to pony up to the likes of Comcast. So that’s nice.

* Wondering what America’s most ridiculously gerrymandered congressional districts are? Christopher Ingraham has the answers, along with the oddball fact that “Democrats won in nine of the 10 most-gerrymandered districts. But eight out of 10 of those districts were drawn by Republicans.”

* Over at the American Prospect, I explained how polls show that there are actually lots of liberal Republicans out there in the land, even if none of them happen to hold office.

* Thirty-seven Senate Republicans, led by (you guessed it) Lindsey Graham, have written a letter to Harry Reid demanding that they get their own Benghazi select committee. In case you thought there was any chance #Benghazi fever would abate anytime soon…

* And here’s the poll question of the day, from Fox News:

In the aftermath of the Benghazi terrorist attacks, the Obama administration incorrectly claimed it was a spontaneous assault in response to an online video, even though the administration had intelligence reports that the attacks were connected to terrorist groups tied to al Qaeda. Do you think the Obama administration knowingly lied about the attacks to help the president during the ongoing re-election campaign, or not?”

As Steve Benen says: “It effectively asks, ‘The administration totally lied. Do you think the administration knowingly lied?'” That’s some fair and balanced polling right there.

What else?