An estimated 15,000 people rallied outside the Capitol today demanding a tax increase.(Tribune photo/Abel Uribe)

Posted by Michelle Manchir and Ray Long at 11:50 a.m.; last updated at 3:12 p.m.

SPRINGFIELD --- Thousands of protesters bused down by labor unions and social service advocates rallied at the Capitol today in an attempt to pressure state lawmakers into raising the income tax to avoid more budget cuts.

A spokesman for Illinois Secretary of State Jesse White estimated the rally crowd at 15,000, with more than 12,000 marching around the building. That would appear to make it the largest Capitol protest since the Equal Rights Amendment crowds a quarter-century ago.

Bus after bus pulled up on streets surrounding the Capitol complex and dumped sign-waving protesters clad in purple, green, red and blue shirts that represented a show of strength from a variety of public employee unions and dozens of groups that formed what they named the “Responsible Budget Coalition.” (You can see a photo gallery by clicking here.)

"Raise my taxes! Raise my taxes! Raise my taxes!" they chanted, lined up shoulder to shoulder for a few hundred yards stretching a street in front of the Capitol.

"These 177 people who have a job don't want to do their job," said Henry Bayer, head of the Illinois chapter of the American Federation of State, County and Municipal Employees, referring to the number of lawmakers in the House and Senate. "Yes people are hurting, that's why we need a tax increase....If you try to leave town without doing your job we're going to chase you."