Process is boring; but process could be everything in the United States Senate as the chamber prepares to debate the "Gang of Eight" immigration reform package.

Partisan bickering over process has derailed bills of lesser import and simpler politics. So, it was worth taking notice on Tuesday when Senate Majority Leader Harry Reid, D-Nev., and Senate Minority Leader Mitch McConnell, R-Ky., discussed in dueling news conferences their views on what would constitute an acceptable floor debate.

McConnell and the Republicans want an "open" process that allows for consideration of dozens -- perhaps hundreds -- of amendments to the compromise legislation. Reid and the Democrats are concerned about GOP mischief -- that Republicans who oppose the legislation might attempt to force votes on extraneous amendments whose only purpose is to kill the bill.

"We certainly know that we're going to be on this bill until the recess. In three weeks I hope and expect we will have a lot of amendments. The 'Gang of Eight' has done their work, and now it's time for the gang of 100 to do its work," McConnell told reporters. "It's an extremely important subject, it needs to be open for all kinds of amendments, and I fully expect that that's the way the debate will be conducted.

Countered Reid a few minutes later: "I want the amendment process to be as open as possible, but ... we're going to need some cooperation from the Republicans. That will mean keep amendments relevant to the issue at hand and not trying to derail this bill with unrelated issues and be very, very careful of senators who have no intention of voting for this bill -- zero -- but they have this wonderful amendment they want to offer to improve the bill, understanding, as I do ... [that] they have no intention of voting for the bill no matter what happens on amendments."

With the "Gang of Eight's" immigration reform package officially under consideration in the Senate, here are three elements to watch as the debate unfolds and heads toward a planned final vote in late June.

1) The process: As discussed, whether Republicans view the debate and amendment process "open" and free-wheeling could determine whether they ultimately vote for the bill. Immigration reform has not elicited the same ire among the conservative grassroots as it did in 2007. But the issue remains politically sensitive, and Republicans are likely to be squeamish about supporting legislation of this magnitude in the midst of charges, fair or not, that the process was rigged for a particular outcome.

2) Senate Minority Whip John Cornyn and his border security amendment. The Texas Republican wants to change the "Gang of Eight" bill to beef up security measures and ensure that formerly illegal immigrants would not achieve permanent residency and eventually citizenship before the border is demonstrably secure. Cornyn's amendment is the kind of proposal that, if adopted, could make several Republicans currently on the fence more comfortable with the bill.

But so far, Democrats aren't biting, meaning they still believe they can garner the needed 60 votes without it. Reid called Cornyn's amendment a "poison pill" and a Democratic source told The Washington Examiner that, at least for now, "Gang of Eight" Democrats view the proposal as "dead in the water." Cornyn, however, painted a rosier picture of his amendment's prospects:

"I think if [the Democrats] had 60 votes to pass the bill out of the Senate, they probably wouldn't be talking to me, but they are, which tells me that they view this as a way to get the kind of support out of the Senate, on a bipartisan basis, that would give it some momentum and increase the likelihood of the bill passing in the House."

3) Sen. Marco Rubio. The Florida Republican's vote could be crucial in passing a measure he played a prominent role in creating. Rubio continues to express optimism that Congress can send an immigration reform bill to President Obama's desk this year. And he continues to speak in mostly positive terms about the "Gang of Eight" bill. But on Tuesday, Rubio proposed his first amendment, one that would strengthen requirements that formerly illegal immigrants demonstrate a proficiency in English to achieve citizenship, signaling that he's serious about needing to change the underlying bill before he'll vote for it.

Immigration reform might still pass the Senate without Rubio's vote. But his opposition to an effort that has progressed this far in large part because of his participation would have suffered a potentially fatal blow as the process shifts to the Republican-controlled House.