The state Capitol snapped to attention Monday when Missouri House Majority Leader Steve Tilley sent out a "tweet'' on his Twitter online account that laid out his predictions about any legislation's chances.

Tilley tweeted that a bill must pass the House this week -- and be on its way to the Senate -- "to have a realistic chance of passage'' before this legislative session ends May 15.

That edict could affect several controversial measures.

Among them: House Joint Resolution 9 (HJR 9), the latest effort by Republicans to require all Missouri voters to show a government-issued photo ID at the polls before they can cast a ballot.

Almost three years ago, the Missouri Supreme Court thwarted a legislative move to impose the government-issued photo ID requirement in the 2006 election. The court tossed out the mandate just weeks before Election Day.

The court said the new law violated Missouri's constitution by imposing "a heavy and substantial burden on Missourians' free exercise of the right of suffrage."

This legislative session, some Republican backers -- including Tilley -- are hoping to circumvent the court and another powerful opponent, Gov. Jay Nixon, by going directly to Missouri voters in 2010 with a proposed constitutional amendment mandating the government-issued photo IDs.

If passed by voters in 2010, the proposed government-issued photo ID requirement would then be in place for the next presidential election in 2012.

The governor doesn't get a chance to sign or veto "joint resolutions'' that propose a constitutional amendment and pass both chambers. Such measures go directly on the ballot.

Backers are banking on a floor vote this week on HJR 9, after the measure won approval last week from the House Rules Committee

Although concerned about the time crunch, Tilley observed recently that a photo ID mandate is "a pretty big issue'' for legislators like himself who support the requirement.

But in the state Senate, potential opponents like Sen. Joan Bray, D-University City, and Sen. Jeff Smith, D-St. Louis, say they will attempt to block HJR 9 -- with a filibuster, if necessary -- if the final version is, as Bray put it, "a piece of junk."

Supporters of the requirement believe that most Missouri voters -- especially those in rural areas -- share their belief that the lack of a government-issued photo ID invites fraud at the polls.

Democrats generally dispute the fraud allegations and say the GOP's real aim is to disenfranchise low-income, disabled and minority voters who are least likely to have government-issued photo IDs, and more likely to favor Democrats.

To sweeten the taste for dissenters, the proposal's sponsors have added a provision authorizing no-fault early voting, which Missouri does not have -- and which many Democrats (and a few Republicans) have long sought.

State Sen. Delbert Scott, R-Lowry City, was among the leaders of the failed 2006 effort to mandate government-issued photo identification at the polls.

He said Monday that he's had some misgivings about seeking a constitutional amendment and about tacking on the early-voting provisions.

"Having said that, if it's the only way to do it and it's a tradeoff for early vote -- I don't know if it's a good idea or not," Scott added. "I am very supportive of the photo ID and certainly am not opposed to the early voting within a certain price tag."

But the two-pronged effort by Missouri's photo-ID supporters appears to have created a new obstacle to their chances of getting the measure through this session -- the Missouri County Clerks Association.

For much of the state, especially rural Missouri, county clerks run the elections.

Missouri's county clerks are split over the photo ID requirement, said association president Stan Whitehurst, the Webster County circuit clerk. But when it comes to HJR 9's early voting mandate, most of the association members are against it.

"As it's currently framed, we don't think the legislation is the right approach,'' Whitehurst said.

By coincidence, the association's membership is gathered in Jefferson City this week for a conference. While in town, Whitehurst added, "We plan to be visiting with our legislators'' to register the concerns about the proposal.

Many association members object to HJR 9's specific language regarding office hours and administrative procedures for early voting, he explained. But what really got the group worked up is the measure's lack of state money to help cover the added election costs that county clerks believe will accompany early voting.

Legislators "don't feel the (financial) pain," Whitehurst said. "If they had some skin in the game, they'd be concerned about the costs of these specific proposals."

The association's concerns could well harm HJR 9's chances, by providing unexpected assistance to various groups who have long been opponents of any Missouri law requiring government-issued photo IDs at the polls.

According to the National Conference of State Legislatures, more than 30 states already allow early voting. Only seven require photo identification.

BATTLE LINES OVER PHOTO IDS AT THE POLLS

The arguments over requiring government-issued photo IDs at the polls have changed little in three years.

Based on state statistics, Secretary of State Robin Carnahan's office believes that up to 240,000 of Missouri's registered voters lack a driver's license -- the chief form of government-issued photo ID that would be allowed under HJR 9. Others put that figure in the range of 160,000 people.

(Those figures were compiled by comparing the number of Missourians with drivers licenses with those on voter rolls. Critics say duplicate voter registrations inaccurately fatten the comparison, and also back up their case that better identification is needed to guard against people voting more than once.)

HJR 9 also would allow a U.S. passport, a military-issued ID or a state-issued photo identification card for non-drivers as an acceptable government-issued ID.

Carnahan's official report of the November 2008 election, which came out last month, declared that there was no evidence of any voter fraud -- but plenty of incidences where legitimately registered people got turned away. In some cases, she wrote, they were improperly told they needed photo IDs.

Carnahan's predecessor, Republican Matt Blunt, asserted in his report after the 2000 election that as many of 1,233 people were illegally allowed to obtain court orders to vote after they couldn't provide evidence that they were registered. Later, the U.S. Justice Department asserted in a lawsuit that an undetermined number of legitimate voters in the city of St. Louis were inappropriately barred from voting in November 2000 because of faulty voter rolls.

In any case, St. Louis lawyer Denise Lieberman, who is the Missouri voter protection coordinator for a nationwide group known as the Advancement Project, says the real issue centers on the real people who are now legitimate voters but could lose their rights if Missouri institutes a constitutional amendment requiring government-issued photo IDs.

"We're not talking about people who would be otherwise ineligible to vote," she said. "We are talking about disenfranchising eligible voters, people who have a right to cast a ballot and have a say in their government, who have been arbitrarily removed from the political process solely because they could not get a copy of an original birth certificate, say, or a student in Missouri with a driver's license from another state or a person with a disability whose signature changes every time."

By a 6-1 vote, the Missouri Supreme Court embraced similar arguments. For example, the court noted that people seeking a driver's license or non-driver photo ID must produce a birth certificate, which can cost $15 to acquire. Such a payment violates the constitutional right to free elections, the court said.

One person who knows firsthand of the frustrations that the photo ID provision can bring is Kathleen Weinschenk of Columbia, Mo., who was instrumental in bringing the suit that overturned the 2006 photo ID law.

Weinschenk, who uses a wheelchair because of cerebral palsy, is unable to write her name and must make a mark while signing documents. Because of her disability, the mark is not the same from one time to the next, so it is difficult to use it as identification.

She said tying the photo ID issue to provisions for early voting undercuts the right she has worked so hard to secure.

"If you have early voting, but not everyone can vote, it still doesn't help anything," she said. "If you have only a selected few people who can vote, you're not a democracy, are you?"

Meanwhile, state Sen. Scott said that requiring government-issued photo identification would provide Missourians with a "great deal of comfort" about the legitimacy of the state's election process.

If Republican legislative leaders are committed, there is time to get the measure through both chambers by May 15, he said.

However, Scott also took note of the potential obstacles facing HJR 9 as well: "I don't know whether it's got legs or not."

Freelance writer Jason Rosenbaum contributed information for this report.