There’s still a lot we don’t know, but it’s being widely reported that the two suspects in the Boston bombing — one of whom has been killed by police — are brothers of Chechen origin. According to law enforcement sources, the brothers entered the U.S. in 2002 or 2003, and at least one of them has been a legal permanent resident since 2007.

Some on the right are already pouncing on the news to cast doubt on the desirability of immigration reform. This morning, Ann Coulter Tweeted:

It’s too bad Suspect # 1 won’t be able to be legalized by Marco Rubio, now.

Bryan J. Fisher is a conservative radio host who rails about the “amnesty” that Senator Marco Rubio — one of the Gang of Eight Senators – supposedly supports in the form of immigration reform. Fischer Tweeted the following in response to today’s news out of Boston:

I think we can safely say that Rubio’s amnesty plan is DOA. And should be. Time to tighten, not loosen, immigration policy.

Meanwhile, over at the Washington Examiner, Conn Carroll, a Rubio critic and immigration reform skeptic, wrote that we still don’t know a good deal about the two brothers, adding that today’s planned Senate Judiciary Committee hearing on the new immigration reform proposal should be delayed. “Today is not the day for an immigration hearing,” Carroll concluded.

Asked for a comment, Rubio spokesman Alex Conant emailed me this:

The situation in Boston is still developing and it’s too soon to jump to conclusions, let alone use the tragedy to make political points.

It’s unclear thus far how widespread the effort among conservatives will be to connect the Boston bombing suspects to the immigration reform debate. But it’s certainly something that bears watching. If this argument picks up steam, it will be another indication of how ferocious the resistance on the right to immigration reform is going to get.

* A primer on Chechen terrorism: A good one is right here.

* Who is Tamerlan Tsarnaev? Foreign Policy has a quick and useful primer on the brother who has been killed. He seems to have had healthy ambitions to be a boxer, but the big unknown is why things went wrong and why he allegedly descended into terrorism.

* Right wing gears up to kill immigration reform: Related to the above, just look at the mobilization that’s already underway among conservatives, documented in today’s big New York Times overview of the immigration debate:

The Federation for American Immigration Reform, which has called for reducing levels of illegal immigration, organized a two-day summit meeting of nearly four-dozen conservative talk radio hosts from around the country. The hosts descended on the nation’s capital to broadcast their concerns to listeners back home that the new bill amounted to “amnesty.” … Senators Jeff Sessions of Alabama and David Vitter of Louisiana, both Republicans, held a competing news conference during which they denounced the bill.

The right is not going to make it easy for the GOP to repair its relations with Latinos or to keep pace with America’s changing demographics.

* Why Senators voted against expanded background checks: This, from the above link, is also telling:

On Thursday, Vice President Joseph R. Biden, Jr., told gun control advocates that several senators had told him they could not vote to support both gun control and immigration: they had the political bandwidth for only one tough vote.

Really? Those Senators couldn’t vote for immigration reform while voting against the assault weapons ban as cover for supporting overwhelmingly popular background checks?

* Senators can only support two difficult issues, not three: Related to the above: Paul Kane reports that multiple Senators have concluded that they can’t support immigration reform, gay marriage and gun control, and guns are the one that fell by the wayside. But let’s be clear here: The real reason more Republicans are going to support immigration reform than gun reform is that they perceive it to be in the party’s long term demographic interests:

After Republican presidential candidate Mitt Romney’s anemic showing among Hispanic voters in November — 27 percent — many in the party feel a more urgent need to reach out to voters in that demographic, and are using the immigration issue to do so.

Supporting gun control, on the other hand, doesn’t really give Republicans anything, which is why only four GOP Senators did the right thing and based their decision in a real evaluation of the actual Toomey-Manchin policy proposal.

* Gun control forces did, in fact, make some progress: Fawn Johnson has a good piece noting that for all the disappointment, proponents of gun reform did move the ball forward:

Supporters of gun control are smarting from the loss, but they can take heart in their progress. Lawmakers finally charged headlong into a debate they have been avoiding for two decades. Gun-owning senators grappled with a compromise, and several of them eventually voted for it…With both sides energized, the issue is likely to surface again—in 2014 congressional races. But if the public remains sharply divided and neither side gains an advantage from the election, the legislative result may be stalemate, once again.

ICYMI: My similar take here.

 * Why we are mired in gridlock: Norman Ornstein and Thomas Mann have a terrific piece explaining how unprecedented obstructionism and deep polarization have made movement on crucial issues — such as climate change, taxes, and the continuing economic crisis — impossible:

[S]erious debates about policy avenues in these areas are impossible if half the political arena believes that climate change is a hoax, and if one political party is animated by the Grover Norquist no-tax pledge and the Mitt Romney vision of a nation of 53 percent makers and 47 percent takers.

In case you haven’t read it, these two guys literally wrote the book on GOP obstructionism.

* The NRA’s previous support for expanded background checks: Glenn Kessler does a deep dive into the history, and finds that NRA chief Wayne LaPierre did, in fact, seem to support a form of expanded background checks in the late 1990s, though it was more of a tactical move than anything else. Key takeaway: The NRA has been playing a clever game — supporting the idea of background checks and claiming they need to be improved while mostly opposing closing the loophole in the law — for over a decade, and it has been working.

* And the case for austerity crashes and burns: Paul Krugman devotes a whole column to one of the topics of the week: The implosion of the research by two Harvard economists that led many governments to pivot from stimulus to austerity, leading to disaster. This seems likely:

So will toppling Reinhart-Rogoff from its pedestal change anything? I’d like to think so. But I predict that the usual suspects will just find another dubious piece of economic analysis to canonize, and the depression will go on and on.

What else?

Greg Sargent writes The Plum Line blog, a reported opinion blog with a liberal slant -- what you might call “opinionated reporting” from the left.