Senator Eliot Shapleigh - El Paso, Texas

AUSTIN — Although legislative leaders still are struggling for an agreement on school funding and tax bills, so little time is left in the session that they now risk any compromise being halted by a Senate filibuster.

A filibuster allows a senator to stall a vote so long as he or she remains standing and talking.

With the regular session due to end Monday and legislative deadlines kicking in before then, critics of a proposed tax reform plan see the potential to stop a measure they say would place a bigger burden on middle- and lower-income groups.

Different proposals passed by the House and Senate would raise business and consumer taxes to cut local school property taxes.

"I think the fear of going from 'Robin Hood' to robbing everyone other than the rich would certainly compel some members to look very closely at the filibuster option," said Sen. Rodney Ellis, D-Houston, one of the tax plan's opponents.

Robin Hood is the name critics gave the current school funding system, which requires school districts with the most property wealth to share some tax revenue with other districts.

House and Senate negotiators theoretically could agree on a tax bill today but the printing process and a 48-hour layout rule could delay consideration until Saturday, thus giving opponents a chance to filibuster.

Sen. Gonzalo Barrientos, D-Austin, has used the filibuster rule twice in his 20-year Senate career — talking for 18 hours and 20 hours.

He has a new pair of Spira running shoes parked under his Senate floor desk. The El Paso-based company uses a system of springs in the shoes to provide more comfort and endurance.

"A filibuster is serious," Barrientos said. "It's almost like using a gun. Don't pull it out unless you are ready to go through with it."

Senate Democrat leaders won't reveal their strategy, but they consider the filibuster a worthy option for stopping consumer tax increases.

"We had a firm agreement not to go over a half-cent increase on sales taxes," said Sen. Eliot Shapleigh, D-El Paso. "Several of us are very concerned with what these bills do to Texans. ... Our goal should be great schools — not tax cuts for wealthy Texans."

The House wants to increase the state sales tax rate by a penny, which, at 7.25 percent, would give Texas one of the country's highest sales tax rates. Local communities can add an extra 2 cents.

Lt. Gov. David Dewhurst, who leads the Senate, said the chamber wouldn't agree to a penny increase in the sales tax.

Barrientos said he and his colleagues have not yet decided who would lead any filibuster.

"We'll be meeting to see who, what and when," he said.

Barrientos figures he's good for at least a 20-hour filibuster, although he said he could use another day's rest to heal a pulled back muscle.

A state judge last year ruled the present school finance system is unconstitutional, saying its heavy reliance on local property taxes amounts to a statewide property tax and that funding isn't enough for an adequate education.

The state is appealing, and the Texas Supreme Court has set a July 6 hearing.

If a compromise is reached, it must pass both Senate and House chambers by midnight Sunday. But the deadline to reach agreement is earlier, since Senate rules require a 48-hour waiting period between the time a tax measure is agreed on by negotiators and printed and when it can be considered by the full Senate.