A decade ago, the very mention of border security was enough to halt progress on comprehensive immigration reform. However, that has since changed, with some lawmakers today still arguing a sticking point that would have had more bite in 2006 and 2007.

The full U.S. Senate will move on Tuesday to begin debating a 2013 immigration bill that’s gaining more momentum and attracting support from conservative lawmakers. Recently, Sen. Kelly Ayotte, R-N.H., publicly announced she backs the bill, calling it a “thoughtful, bipartisan solution to a tough problem.”

Despite all this good news on immigration reform, the Senate's Gang of Eight -- four Democrats and four Republicans -- who drafted the bill are expecting major push-back from those squeezing for more enhanced border security before the 11 million undocumented immigrants are provided a path to citizenship. But any border security amendments seeking to take away from the core of the bill may face opposition and here’s why:

Net Migration From Mexico Already At A Standstill

Approximately 6.1 million unauthorized Mexicans were leaving the U.S. as of 2011, according to Pew Research Hispanic Center, while legal immigration increased 3.4 percent to 5.8 million. This success has been attributed to several factors that include a weak American job and housing construction market, increased border security, the growing danger of illegally crossing the border, higher deportation rates and declining birth rates in Mexico, as well as improved economic conditions.

Making a path to citizenship contingent on enhanced border security appears to not be in line with the reality: It's time to do something about the 11 million people already here. The bill the Senate will begin debating has proposed policies to safeguard the border, deal with the status of those already here, make the legal immigration system much more lenient, and ensure employers don’t break the law.

“One of the main misleading arguments out there is that enforcement is the only way we can stop illegal immigration,” Alex Nowrasteh, an immigration policy analyst for Cato Institute, said. “One of the most effectively ways to stop illegal immigration is to actually increase the number of legal immigrants who can come, thereby channeling them into the legal market. That has been the most effective in the past and will likely be the most effective going forward.”

More Boots Are Already On the Ground

It might sound like a cliché, but the border is really more secure than ever. Senators like Alabama’s Jeff Sessions who have remained skeptical of improvements in border security probably haven't been looking at the statistics. However, much of the failings of the 1986 attempt at immigration reform have now been corrected or are getting there. The number of border patrol agents has more than double what it was in 2004 to 21,000 today, according to the Center for American Progress. More than 18,000 of those agents are deployed along the Mexico border, and drones are out patrolling as well. Additionally, while there weren’t any legal avenues for low-skilled workers to enter the U.S. with status or any E-Verification system, lawmakers are looking to create a low-skilled worker visa called W-visa.

“So this bill actually really takes care and takes a holistic approach to actually solving the problems that in 1986 didn’t get solved,” Philip Wolgin, senior policy analyst for immigration at the Center for American Progress, said.

Americans No Longer Buy Into Enforcement First

As some lawmakers remain stuck arguing issues of relevance 10 years ago, more Americans seem to have moved away from the border-enforcement-first concept. According to a recent poll by Quinnipiac University, 51 percent of voters support a path to citizenship for those already in the U.S. Only 29 percent prefer deportation. The faith these voters have in lawmakers not passing an actual immigration reform bill is very high, as 71 percent of the near 1,500 voters polled believe Democrats and Republicans won’t be able to work together to achieve it.

The experts, however, are a bit more hopeful.

“I think it will pass, because Republicans worry about the national picture,” Harry Holzer, professor of public policy at Georgetown University, said. “They are worried that opposing this could be suicidal. They want Republicans to have a shot at getting these voters in 2016, 2020 and beyond.”