Is the bipartisan immigration reform led by the "Gang of 8" a breakthrough on a seemingly intractable issue -- or deja vu all over again?

Marchers carry signs in support of immigrant rights as thousands of protesters march up Broadway during a May Day immigration rally in Los Angeles, California. (Reuters)

In judging whether immigration reform will succeed, it's helpful to know why so many past attempts by Congress and the White House to change the system have failed. Here's a timeline of the major attempts to deal with illegal immigration and why they didn't make the cut.

* The Immigration Reform and Control Act of 1986: The amnesty law of 1986 passed through Congress and was signed by President Ronald Reagan, but it is largely considered a failure. The legislation was meant to tighten border security and crack down on employers hiring undocumented immigrants, while offering amnesty to those already in the country illegally. Three million immigrants were legalized, but the law did not slow illegal immigration or create a framework to deal with it going forward. Since then, opponents of comprehensive reform have often cited the 1986 legislation as a reason to be wary.

"For 20 years our country has done basically nothing to enforce the 1986 legislation against either the employers who hired illegal immigrants or those who crossed our borders illegally to work for them," then-Arizona Governor, now Homeland Security Secretary Janet Napolitano wrote in 2007.

* 1996: Under President Clinton, most reform was aimed at reducing immigration amid rising anti-immigrant sentiment in the country. But the backlash against strict reform led many of the harshest measures to be rolled back, meaning that ultimately little changed.

Partisan and intraparty disputes over how far to go caused multiple delays. Attempts at a national identification card went nowhere, as did legislation -- introduced by Sen. Harry Reid (D-Nev.) -- that would deprive the children of undocumented immigrants of citizenship. (Reid apologized for that legislation in 2006, calling it  the "low point" of his career.)

Clinton ultimately signed a spending bill that included increased border security and made it harder to get asylum in the U.S.. Attempts at harsher measures, such as barring undocumented immigrants from public schools and limiting legal immigrants' access to health and welfare services, were watered down. Most were rolled back by Republicans after their Latino support dropped markedly in the 1996 election.

* 2000: President Clinton pushed for amnesty for hundreds of thousands of immigrants left in legal limbo by a technical screw-up involving the 1986 law and offered a path to citizenship for hundreds of thousands of Central Americans. Republicans blocked that effort, but (again mindful of electoral concerns) passed their own legislation addressing the 1986 issue and family members of legal residents. Clinton threatened another showdown, but after Democrats lost the 2000 election he backed off and signed the GOP bill.

* 2004-2007: You could say that talk radio killed President Bush's attempts at immigration reform. He hoped to appeal to both business owners and Hispanic voters with a comprehensive overhaul, but he was stymied by his own party.

Bush began pushing for a guest worker program in 2004. An early attempt by Sens. Chuck Hagel (R-Neb.) and Tom Daschle (D-S.D.) died a quick death, in part because of election year politics. But even the prospect of reform stirred up a backlash from conservatives, in particular Rep. Tom Tancredo (R-Colo.). Tancredo appeared on talk radio constantly warning of the dangers posed by illegal immigration.

Bush allies attempted to fight back with a corporate-funded PR campaign, but business leaders wouldn't donate, concerned that conservatives would pressure Bush into signing something that actually made it harder to hire from overseas. In fact, then-Majority Leader Tom DeLay (R-Texas) pushed for an enforcement-only approach. The comprehensive bill introduced by Sens. Edward Kennedy (D-Mass.) and John McCain (R-Ariz.) in 2005 could not be reconciled with a tough enforcement-only House version that sparked protests.

Bush tried again in 2007, crafting a compromise that allowed a path to legal status for current immigrants and a new temporary worker program, contingent on stricter border security and employer crackdowns. The legislation resembled a conservative approach offered by Sens. John Cornyn (R-Texas) and Jon Kyl (R-Ariz.) in 2005.

"We misread" the situation, said Frank Sharry of America's Voice. Advocates thought that with Democrats in control of Congress, Bush would try a moderate approach again and succeed. Instead, "Republicans were beginning what we might call the advent of the tea party -- they started to lurch to the right, they wanted to give Bush a bloody nose, the conservative media mobilized."

The AFL-CIO turned against the legislation over the guest-worker program. (The Service Employees International Union, with its many immigrant members, supported it). But despite the legislation's more conservative tilt, the talk radio blitz continued. Ultimately conservative Republicans, along with several pro-labor Democrats, opposed the legislation and it died in the Senate.

* 2010: Like Bush, President Obama was caught between Hispanic voters and the GOP. In 2009 he called immigration reform a priority but acknowledged that there was too much on his plate to get it done soon.

By early 2010, Obama faced pressure from immigration advocates to move forward. He pushed for comprehensive reform, and Sens. Chuck Schumer (D-N.Y.) and Lindsey Graham (R-S.C.) collaborated on legislation. But after a bruising fight over health care and in the face of a tough midterm election, the push unsurprisingly went nowhere. When Reid promised to fast-track the bill, Graham accused him of engaging in a "cynical political ploy" to win Hispanic votes and pulled out of the talks. Reid backed off. Obama himself acknowledged that "there may not be an appetite" for immigration reform that year.

Immigration reform has suffered from the same few problems for years. Business interests and labor interests have to find a way to reconcile their disagreements. Conservatives who want enforcement first -- or enforcement alone -- have to be placated. Electoral concerns push lawmakers one way and then the other.

Optimistic advocates argue that the calculus has now changed. Protests in support of the DREAM Act (another immigration initiative prone to failure) has brought national attention to the plight of young undocumented students. States have started to experience the negative economic impact of strict immigration laws. And most importantly, the 2012 elections showed Republicans that they can no longer rely almost entirely on white voters to win. They also showed that Obama faced no backlash over an executive order that protected some undocumented immigrants from deportation.

"What's different about this moment is that we have the moral, the economic and the political imperatives for why we need immigration reform fully in line," said Clarissa Martinez, director of immigration and civic engagement at the pro-reform National Council of La Raza.

It could be. But if immigration reform succeeds, it will go against a quarter-century of political history.