Former South Carolina Sen. Jim DeMint, the new president of the conservative Heritage Foundation, ripped the bipartisan “Gang of Eight” U.S. Senators who are pushing immigration reform during the debut of Breitbart News Sunday with Stephen K. Bannon on Sirius/XM Patriot on Sunday night.

“That’s not the way it should be done, where people go behind closed doors and come up with something that we still haven’t seen,” DeMint said.

They’re out there selling it. We don’t know what the legislation is but we’re supposed to have an open, democratic process where people can hear the debate, they can see amendments, they can find out what’s in the bill before it’s voted on. So, it’s very frustrating. Obviously, this isn’t the first time this has happened–on the fiscal cliff, and on all these other things they do backroom deals. But I’m tired of it. Frankly, it’s one of the reasons I left the Senate: to try to change things from the outside in. But I know some of these folks involved [in the Gang of Eight] are actually trying to solve a problem, but this is not the way to do it.

DeMint said Sen. Marco Rubio (R-FL) is one of those he thinks is actually trying to solve the problem of illegal immigration but is going about it the wrong way–mainly because the way Washington has evolved is antithetical to transparent and open government.

“Well this is hard because Marco is one of my best friends in the Senate and he’s a great guy, very genuine, and I know he got into this process trying to solve a problem,” DeMint said when asked for his reaction to Rubio’s whirlwind media tour this weekend, in which the Florida Republican appeared on a record seven Sunday shows.

“He’s just dealing with some folks who have a political objective and it’s very difficult,” DeMint explained. “So, I don’t blame him for trying to sell what’s in it, I’ve just encouraged him from the very beginning to make sure he knows what’s in the legislation and make sure we get what we need out of a new immigration system before we agree to make citizens out of 11 million people.”

The eight senators–Republicans Rubio, Jeff Flake, John McCain, and Lindsey Graham and Democrats Bob Menendez, Chuck Schumer, Dick Durbin, and Michael Bennet–have been meeting in secret since January trying to craft a plan for comprehensive immigration reform.

White House officials have been involved in the drafting of the legislation, as have representatives from special interest groups like the powerful AFL-CIO labor union and the big business lobby the U.S. Chamber of Commerce. Representatives from groups in favor of law enforcement reform, like the president of the Immigration and Customs Enforcement (ICE) agents’ union Chris Crane, have been kept out of the discussion, as has anyone opposed to granting amnesty to illegal aliens.

DeMint claimed that the reason those senators keep the deal-making happening in secret is because their plan cannot stand up to public scrutiny. “One of the reasons you do all this behind closed doors is because you don’t want any critics at the party,” DeMint said.

You want to bring this out and surprise people and do your pre-selling. But, Robert Rector, just about five years ago, when I was helping to fight a similar bill, provided information that was not only credible but it was very provable that there is a high cost to have amnesty. There is a high cost to have unregulated immigration and we need to go ahead. Americans are going to look at this very differently if they know it’s likely to mean they’re going to cut their Social Security and Medicare and raise their taxes which the president seems to be talking about every week.

Heritage Foundation analyst Robert Rector is in the final stages of wrapping up what is expected to be a bombshell analysis breaking down the entire cost of the Gang of Eight’s immigration reform proposal. Preliminary estimates from Rector’s and Senate Budget Committee Republican staff analyses put the Gang of Eight plan at just under $3 trillion in entitlement spending increases, but the final analysis may put the number much higher.

As the Heritage Foundation continues its work on this, the conservative hallmark has taken heat from several groups around Washington for the forthcoming report–largely because the Heritage report could very well be the poison pill that kills immigration reform.

The libertarian Cato Institute and the GOP establishment-minded Americans for Tax Reform, Grover Norquist’s group, have become unlikely allies, banding together to attack the still-unpublished Heritage analysis from Rector.

During his media tour this weekend, Rubio himself stabbed at Heritage, saying on Fox News Sunday that Rector’s forthcoming analysis was not accurate. DeMint said he trusts Rector, and added that this report coming out “shouldn’t be controversial.”

“Those who don’t think this has been done correctly should show us their analysis,” DeMint said. “The fact is, there is not any other analysis. Robert Rector has been a scholar for years. He was the one who did the data that actually ended up pushing through welfare reform back in the 1990s,” he explained. “He came out with data that was irrefutable five years ago [on immigration costs], although some are saying it needs to be combined with other types of research.”

DeMint argued that the report should be a point of open analysis of the plan: “Let’s talk about it. But let’s at least consider the cost. We hope we’ll have our report out within the next week. We’ll be writing and speaking about it a lot but Americans need to understand there’s nothing free about the proposal that’s being talked about.”

As the bill is set to be released on Tuesday, DeMint urged Americans and those in the media to “keep in mind that even if it’s in legislation that does not mean the administration will do it.”

“Over five years we passed into law that there had to be 700 miles of double layer fencing along the volatile areas of our southern border,” DeMint said. “But President Obama has ignored the law.”

There are only 30 something miles of double layer fencing that have actually been built. The law says that the federal government should support states in the enforcement of federal immigration policy, this administration has decided not to do it. So my point is this: if they promise legal status or citizenship in return for the future fixing of the immigration system, no one can count on that. That’s why this needs to be a step-by-step process where we fix the system first and earn the trust of the American people, then we consider what we’re going to do with those who are already here.

But as Sen. Jeff Sessions (R-AL) noted in a Sunday afternoon press release, the Gang of Eight senators admitted throughout their Sunday show blitzkrieg that they want to do amnesty first, then reform the immigration system later.