It looks like we may soon get our answer to the question that could decide the fate of immigration reform: Is there any level of border security in the reform bill — short of measures deliberately designed to kill reform — that can get conservative Republicans to accept the path to citizenship?

In a major boost to reform, multiple reports this morning confirm that a bipartisan group of Senators, including the gang of eight, is nearing a deal on measures toughening up the security provisions in the gang of eight bill. By any reasonable measure, the compromise gives conservatives a good deal more in the way of border security.

The key items, according to reports and sources, are: A doubling of the size of the border patrol, to 40,000 agents. Seven hundred miles of border fence. A requirement that the security plan submitted by the Department of Homeland Security include provisions — such as those above — mandated by Congress. All of these would be “triggers” that would have to be achieved before the path to citizenship can start.

But — and this is big – the provision sought by conservatives such as John Cornyn, that 90 percent apprehension be achieved as a “hard trigger,” is no longer in the deal as a precondition for citizenship. As the Times puts it: “Republicans agreed to make the 90 percent figure a goal rather than a requirement.” The key is that additional Republicans beyond the gang of eight — such as Bob Corker and John Hoeven — appear prepared to accept this.

Leading immigration advocate Frank Sharry, who was briefed on the emerging deal, tells me Dems successfully beat back Republican demands for inclusion of the 90 percent “hard trigger.” And so Sharry’s group, America’s Voice, can support the deal, albeit reluctantly.

“The deal is ridiculous from a policy point of view — it’s excessive and wasteful,” Sharry tells me. “But from a political point of view, if it brings 10 or 11 Senate Republican votes, we’ll probably will be able to live with it.” Sharry says this is because the current triggers in the emerging compromise are “doable and achievable.”

And this really is the rub. Dems suspected Cornyn’s demand for a 90 percent apprehension rate trigger was deliberately designed as a metric that could be gamed later to kill citizenship. On-the-fence Senate Republicans had gravitated towards Cornyn’s amendment. But Dems and Repblicans on the gang of eight appear on the verge of turning back that challenge, and are close to carving out a space where more undecided Republicans can support reform while claiming they successfully held out for tougher border security provisions, without killing it.

Indeed, this morning, the office of Marco Rubio — who is being closely watched by GOP fence-sitters — blasted out an interview in which the Senator described the emerging deal as one that would “substantially increase” border security. That strongly suggests Rubio can support it; if both Rubio and Sharry can back it, that suggests real consensus and bodes well. Indeed, multiple reports say Republican Senators may get behind this in sizable numbers.

In short: We may be witnessing the defeat of a major conservative drive to kill reform. But by any measure, the emerging deal does give conservatives plenty more in border security. What will be particularly interesting is how House Republicans react. Is there any level of border security that can get conservative Republicans to accept citizenship?

* TIME FOR REPUBLICANS TO PICK A SIDE ON IMMIGRATION: Related to the above, E.J. Dionne’s column today gets it right: Republicans need to decide whether they will support the emerging consensus around a combination of a path to citizenship and toughened up border security, or whether they will instead oppose reform. Dionne:

Changes that so complicate a path to citizenship for illegal immigrants as to render it meaningless are (and should be) unacceptable to supporters of reform, including most Democrats. But if the GOP senators accept something short of this, they will face furious attacks from the hard-core opponents of any move toward large-scale naturalization of those who came here illegally. In the end, there is no way around their dilemma. If they want a bill, they will have to take political risks.

Republicans must decide whether beginning to repair long term relations with Latinos is worth dealing with the consequences from the base.

 * GOP LATINO OUTREACH COLLIDES WITH TEA PARTY RAGE: This Roll Call account of Tea Partyers at a rally heckling lawmakers involved in the push for immigration reform really says it all about the state of today’s debate. It’s a perfect expression of the right’s adamant refusal to allow the GOP to evolve along with demographic and political realities.

* BUT IT ISN’T JUST THE TEA PARTY: Speaking of that Tea Party rally, Steve Benen gets it right on the broader context here:

What have Republicans shown the nation lately? There was a Tea Party rally this week, which followed a big fight over an anti-abortion bill that can’t pass. In the states, we see a focus on culture-war issues, including state-mandated, medically-unnecessary ultrasounds. On Capitol Hill, most Republican lawmakers are running around talking about “amnesty” and “illegals,” which is every bit as insulting as their rhetoric about women.

Yesterday, we even heard talk about “takers,” as if the “47 percent” video never happened. And on the horizon, many in the GOP are already planning another debt-ceiling crisis.

Yes, that GOP “rebranding” continues apace…

* DEMS LAUNCH AD CAMPAIGN AGAINST MITCH MCCONNELL: Two outside groups allied with Democrats are launching a new ad in Kentucky targeting Senator Mitch McConnell as a career politician who voted to raise his own pay, bail out Wall Street, and cut benefits for seniors. The groups — the Senate Majority PAC and the Patriot Majority USA — say it’s the start of a major, multi-faceted media campaign.

Dems do appear to believe it’s not impossible that their preferred candidate (Kentucky Secretary of State Alison Lundergan Grimes, who hasn’t yet said whether she’ll run) could beat McConnell, though it’s likely a long shot.

* OBAMA FACES PRESSURE FROM LEFT OVER KEYSTONE: More than 100 former Obama campaign workers is sending a letter to the President demanding he oppose the controversial Keystone XL oil pipeline project. Still unclear: If Obama does end up supporting the project, how will the White House square that with its vow to make a major climate change push this summer?

* SCOTUS SET TO RULE ON GAY MARRIAGE CASES: With the Supreme Court set to hand down rulings as early as this week on two big cases involving gay marriage, the Post has a great interactive graphic that lays out all the different potential outcomes in both cases, and what they would mean for the marriage equality fight going forward. One key thing to watch for: whether the High Court will strike down Proposition 8 with a broad ruling finding it unconstitutional, which could give advocates the tools to target other state laws and eventually put opposition to marriage equality on path to extinction.

* HOW SCOTUS MIGHT VIEW GAY MARRIAGE CASES: I’d missed the significance of Senator Lisa Murkowski’s statement in support of gay marriage yesterday, but Jonathan Capehart does a nice job explaining why it matters and why her rationale could help inform a conservative SCOTUS ruling on gay marriage that could have long term implications.

* A REALITY CHECK ON THOSE APPROVAL POLLS: MSNBC’s First Read crew really gets this right in its morning First Thoughts email (no link yet):

Every political journalist and observer, including us, is guilty of drawing conclusions from just one poll. And yesterday, we received another reminder of the pitfalls of that practice. After a CNN survey (conducted June 11-13) found that President Obama’s approval rating had dropped to 45%, a Pew poll (conducted June 12-16) found it steady at 49% approve/43% disapprove….Folks, drawing conclusions from just one poll is like eating a box of donuts for breakfast — it tastes great and it’s different than your usual breakfast meal. But you usually regret it later.

Yup. Stick to the polling averages.

* AND THE TEA PARTY TURNS ON MARCO RUBIO: Back to immigration! Dana Milbank has a good, if unsettling, read detailing the rage that the Tea Party is now directing at Marco Rubio for daring to try to fix the country’s broken immigration system, after turning him into one of their heroes and lifting him to power during the 2010 wave election. Of course, it’s hard to sympathize with Rubio here, given his own role in letting the Tea Party genie out of the bottle. Live by The Crazy, die by The Crazy…

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.