Yesterday the U.S. Senate set down the path toward the most significant shift in U.S. immigration policy in two generations. It has been more than a quarter century since the last significant immigration legalization passed. In the period since then, immigration laws have hardened and immigration enforcement has expanded beyond what even hardline immigration restrictionists dreamed. So when a bi-partisan group of senators appeared yesterday on a Capitol Hill stage to declare 2013 the year of immigration reform, they restored a vision of a way forward for many. The senators released a document of guiding principles that provides a path to legal residency for many of the country’s estimated 11 million undocumented immigrants. It also creates avenues for new immigration, while bolstering immigration enforcement at the border and in workplaces. If these principles lead to a bill, as expected, it could transform the social and political fabric of the country. Yet even as senators yesterday offered a genuine reform outline, with striking new areas of consensus, some worry they also wove into the agreement enough loose strings to cause its unraveling. **A New Political Landscape** The framework released yesterday by four Republicans and four Democrats is a dramatic shift for the GOP. Republicans have repeatedly refused to support what many pejoratively call "amnesty," demanding first that before creating legal residency for undocumented immigrants, the border must be fully secured. Most observers agree that the 2012 elections changed the terms on immigration reform, shaking the GOP out of its entrenched obstructionism on the issue. Latino and Asian voters turned out by broad margin against Mitt Romney and it’s been widely noted that the Republican candidate’s hardline position on immigration helped lose him the election. "As I’ve stated before, elections, elections," Arizona Sen. John McCain said at yesterday’s press conference announcing the principles he helped draft. McCain was part of previous attempts to reform immigration law. "The Republican Party is losing the support of our Hispanic citizens, and we realize there are many issues in which we think we are in agreement with our Hispanic citizens, but this is a pre-eminent issue for those citizens." The eight senators who drafted the principles now agree that ultimately, those living in the country without authorization who pass a set of tests and hurdles should be allowed to apply for citizenship. This agreement marks a significant shift in the debate. "The fact that there’s no quibbling about citizenship is huge," said Lynn Tremont, the deputy director of America’s Voice, a leading immigration reform group. Tremont and others add that relative to what many advocates feared, the initial principles from the senators do not include significant investments in new kinds of enforcement or paths to deportation. Past iterations of immigration reform have included more stringent enforcement provisions than what’s included in the senate platform, and certainly many Republicans will try to squeeze in more once negotiation begins on actual legislation. But "so far," says Tremont, "I have not seen anything in the principles that’s gratuitous." Few observers think immigration reform will have an easy journey to the president’s desk. Veteran Republicans like McCain and South Carolina Sen. Lindsay Graham can take a long view about the party’s future, as can Florida Sen. Marco Rubio, who is staking his likely 2016 White House run on votes from Latinos. But many Republican members of Congress from conservative districts can’t get behind an immigration reform bill if they hope to keep their jobs. This is especially true in the House, where incumbents still tremble before the memory of the tea party’s 2010 sweep that pushed out moderate incumbents. Still, there’s little doubt the landscape has changed. "For the first time ever there’s more political risk in opposing immigration reform than in supporting it," said Sen. Chuck Schumer, a leading Democrat on immigration reform and a member of the Senate Judiciary Committee, where a bill will first land. Along with Schumer and McCain, the drafters include Democratic Senators Michael Bennet of Colorado, Dick Durbin of Illinois, and Bob Menendez of New Jersey and Republican Senators Jeff Flake of Arizona, Graham and Rubio. **Will Border Security Undercut Reform?** The question remains what pre-conditions Republicans will demand for creating paths to citizenship. Many warn that, despite newfound agreement on the need to offer existing undocumented residents routes to legal residency, the senators tucked into their language opportunities for the same old obstructionism. This is particularly true in the principles around border security. Legalization, the senators wrote, is "contingent upon our success in securing our border…to prevent, detect, and apprehend every unauthorized entrant." The language sounds a lot like the old Republican demands that derailed reform efforts. The plan would grant undocumented immigrants who pass background checks and pay fines a *provisional* status that allows them to work legally, but until the border is secure, there will be no path to citizenship, according to the document. Securing the border has become a trope in Washington that must be uttered by members of both parties whenever they so much as whisper about legalization. Few imagined the Senate proposal would flout this unspoken rule. But the language in the Senate framework demands border security as a precondition before anyone gets in the citizenship queue, and that raises red flags for reform advocates. Rep. Raul Grijalva is a progressive immigration reform proponent from Arizona. He says the guidelines released yesterday are an exciting sign of progress, an opening to move forward. But he told Colorlines.com that the idea that the border has to be secured before immigrants can apply for citizenship threatens to undermine the promise of the legislation. "Any transgression at all will be used to make the border look less secure," said Rep. Grijalva. "It’s an impossible standard. At what point is it secure?" According to the guidelines, a "commission comprised of governors, attorneys general, and community leaders living along the Southwest border," will be tasked with evaluating when the border is sufficiently closed. But when questioned yesterday, none of the senators explained how the system would work and what kind of power the commission would have. "The concern I have is that it’ll be a highly politicized body they’d never acknowledge that we’ve reached a place of security on the border. Governor Brewer and Tom Horn have made their political careers on stringent anti-immigrant agenda," Grijalva said of the Arizona governor and attorney general who helped usher in their state’s notorious immigration laws. Others say worries like Grijalva’s are outsized because the commission won’t have that much power. A Hill staffer who worked on the guidelines told Colorlines the senators imagined a commission comprised of an "equal number of Democrats and Republicans," adding that the legislation itself would provide commission members with a clear list of factors that indicate border security. "They do not have an automatic veto–it’s an internal check on whether the [Department of Homeland Security] is doing what the bill says it has to do," the staffer said. The list of preconditions in a bill might include additional drones to patrol the border as well as added surveillance technologies and more border patrol guards. Democratic members of Congress have been consistently clear that they will not accept a reform package that does not include a certain route to citizenship. Today, President Obama will deliver a speech in Las Vegas on immigration reform and he is expected to draw that line even more firmly in the sand. Ultimately, some worry that skittish Republicans will back away from a path to citizenship, or use the committee to demand impossible preconditions. But for now, the most promising drive to reform immigration laws since 1986 continues full steam ahead.