By Joanna Allhands The Republic | Tue Feb 19, 2013 1:18 PM

How likely is comprehensive immigration reform to pass?

Former U.S. Rep. Jim Kolbe, who was involved in previous reform efforts, gives the current one a 50-50 chance. He says he is heartened by bipartisan involvement but also troubled by President Barack Obama's plan, which offers no details on creating a realistic guest-worker program.

Kolbe spoke to The Republic's editorial board Tuesday.

The Republican former congressman says comprehensive immigration will live and die on four pillars: Border security, temporary workers, employer enforcement and a path to citizenship for the estimated 11 million undocumented immigrants already living here. If the bipartisan "Gang of Eight" produces legislation that addresses all four pillars, Kolbe says, that will raise the odds of passage in the House.

Meanwhile, Kolbe says, we shouldn't hold our breath on an 11th-hour deal to avoid sequestration, the automatic budget cuts that threaten to cripple Arizona's lucrative aerospace and defense industry. Republicans view the cuts as their only bargaining chip to press for entitlement reform, which Democrats have been loath to address.

Jim Kolbe: Immigration reform has a 50-50 chance