Illinois Democrats plan to raise the state income tax by 67 percent in January, Governor Pat Quinn's budget director recently told Bloomberg Businessweek.

“We fully expect that we’re going to pass a tax increase in January. We expect it is going to be substantial,” Quinn budget director David Vaught told the national business publication.

Vaught said an increase from the current 3 percent to 5 percent is likely. It would cost taxpayers $6 billion and would be the largest tax hike in Illinois history.

In 2009, Democrats in the Illinois Senate approved a similarly-sized tax increase, but the House has not acted on that increase. It's unclear from Vaught's remarks if he was referring to that increase – which could yet be passed by the House – or if he was referring to a new proposal. Although Governor Quinn sought to distance himself from the 67% tax hike shortly after Vaught's remarks became public, the Governor has consistently supported income tax increases, while making the exact rate a moving target. In 2009 he proposed a 50% tax hike, while he has more recently suggested a 33% hike.

However, Vaught pointed out in the interview that Quinn did testify before a House Committee in favor of the Senate Democrat's 67% income tax increase after it passed the Senate in 2009. 

Senate Republicans have consistently said raising taxes would hurt consumers and could have a deadly effect on job-creation at a time when Illinois is already suffering from some of the highest unemployment rates in the nation. Republicans also point out that any tax increase, without core reforms to state government, will only offer temporary relief and lead to even more tax hikes in the future.