A proposed 2010 ballot measure appears to roll back property tax actions passed after 1992, but legislators aren't sure because they say the language is confusing.

"Honestly, I don't what they're trying to do here," Rep. Mark Ferrandino, D-Denver, said after reading the proposal.

Sen. Josh Penry, R-Grand Junction and Senate minority leader, said: "I'm torn. I love tax cuts, but I have a longstanding policy against run-on sentences and non sequiturs in the Constitution."

Other lawmakers who reviewed it said the authors might be unwittingly giving undocumented immigrants the right to vote. That's because it allows Coloradans to vote on property tax issues in any district where they own taxable property.

The proposal was filed Tuesday by Bonnie Solan, of Black Hawk, a mortgage planner, and Lou Schroeder, of Greenwood Village. Neither returned phone calls.

Schroeder is huge fan of Douglas Bruce, author of the 1992 Taypayer's Bill of Rights. Schroeder last year nominated Bruce as "Man of the Year" on a conservative blog.

The proposal would amend TABOR to include various property tax provisions.

It states: "Prior actions to keep excess property tax revenue are expired."

Ferrandino, who sits on the Joint Budget Committee, said he believes the proposal is related to a controversial property tax law that Democratic Gov. Bill Ritter and the Democratic-controlled legislature approved in 2007.

The law froze property tax rates in most of the state's school districts, blocking a scheduled dip in property taxes. The freeze means higher tax bills for owners of property that has risen in value.

The law is expected to raise an additional $1.7 billion for schools over 11 years.

Opponents sued, arguing the law is unconstitutional because TABOR requires voter approval of tax increases. The case is pending before the Colorado Supreme Court.

Ferrandino said he's not sure if the measure would reduce the property taxes available for school districts. If it does, the state might have to backfill district budgets.

That could wipe out the state's general fund budget, which provides money for prisons, motor vehicle offices and such, he said.

Filing a proposal with the Legislative Council is the first of many steps of getting a measure on the ballot. If the proposal survives those steps and is approved by voters in 2010, it would go into effect in 2011.