Illinois has been in waiver purgatory the longest.

The state applied in February 2012, and has been languishing (though not officially rejected) because its teacher-evaluation implementation timeline wasn’t fast enough for federal approval.

But now that U.S. Secretary of Education Arne Duncan has offered waiver states a one-year delay in tying personnel decisions to teacher evaluations, this could open the door for Illinois to win approval.

Under Illinois law, a new teacher-evaluation system created under state law is being phased in and will be fully implemented—including with consequences for teacher ratings—by 2016-17. That’s the revised deadline Duncan has set amid a chorus of complaints that states need more time to adjust to new common standards and tests.

Suddenly, Illinois and the feds are aligned—at least for the end date.

The problem that remains for Illinois is year 2015-16. Under its law, that’s still a transitional year for schools and not all schools will be using the new teacher-evaluation system. But under the federal waiver requirements, all schools need to be using the new system that year—just not for personnel decisions under Duncan’s timeline shift.

So what does this mean for Illinois? State officials aren’t sure yet. A spokesman for the Illinois Board of Education told me state education officials have asked these very questions of the federal Education Department, and are awaiting a response.

Clearly, with last week’s announcement, Duncan has shown a willingness to shift his thinking on flexibility requirements. After all, he’s considering a first-of-its-kind waiver to several California districts because the state hasn’t been able to get a waiver of its own. Perhaps Illinois should ask for its own special waiver, too.