WASHINGTON – Proponents of immigration reform cleared a major hurdle on Tuesday as the full Senate agreed to debate proposed legislation – but the chances for ultimately getting the package through the upper chamber remain foggy.

In a rare 82-15 bipartisan vote, including 30 Republicans voting yes, in what has been a divisive session, the Senate agreed to move the bill along despite the reservations of conservatives – including Sen. Marco Rubio (R-Fla.), one of the prime authors – that it doesn’t concentrate sufficiently on security.

Senate Republican Leader Mitch McConnell (R-Ky.) voted to permit the debate to proceed, joining others in opposing a filibuster to block debate. But that doesn’t mean he supports the legislation and that attempts to derail the effort won’t crop up in the future.

“I’ll vote to debate it and for the opportunity to amend it, but in the days ahead there will need to be major changes to this bill if it’s going to become law,” McConnell said. “These include, but are not limited to, the areas of border security, government benefits and taxes.”

McConnell said he will need more than assurances from Homeland Security Secretary Janet Napolitano that the southern border is secure before he’ll agree to support the measure.

“Too often recently, we have been reminded that as government grows it becomes less responsible to the American people and fails to perform basic functions either through incompetence or willful disregard of the wishes of Congress,” McConnell said. “Our continued failure to secure major portions of the border not only makes true immigration reform far more difficult, it presents an urgent threat to national security.”

McConnell said he is also listening to critics who maintain the bill will prove costly to American taxpayers.

“It’s a fair critique,” he said. “Those who were here illegally shouldn’t have their unlawful status rewarded with benefits and tax credits. So this bill has some serious flaws. And we need to be serious about fixing them. The goal here should be to make the status quo better, not worse. And that’s what the next few weeks are about — they’re about giving the entire Senate, and indeed, the entire country, an opportunity to weigh in on this debate, to make their voices heard, and try to improve our immigration policy.”

Sen. Dan Coats (R-Ind.) also cast a shadow over the bill’s future even though he acknowledges the current immigration system “has failed the citizens of this country.” He expressed particular concerns about border security measures

“We cannot just trust that the border will get fixed,” he said. “Steps must be taken now to secure our borders, expand employer verification and improve the existing exit system. Fixing our immigration crisis is critical to growing our economy and strengthening national security.”

The 1,076-page Border Security, Economic Opportunity and Immigration Modernization Act of 2013, as it currently stands, creates a pathway to citizenship for the estimated 11 million immigrants who entered or remained in the country without proper documentation.

Under the bill, illegal immigrants who have resided in the U.S. since Dec. 13, 2011, must seek provisional legal status that allows them to work but renders them ineligible for federal benefits. They must pay a penalty, taxes and a processing fee and can only apply for permanent status after 10 years.