JEFFERSON CITY — Republican lawmakers are set to test their veto-proof majorities today — Wednesday — after discussing strategy in caucuses Tuesday evening.

Democratic Gov. Jay Nixon vetoed a 29 laws passed by the Republican-led legislature, but the GOP holds a narrow, two-thirds majority in both the House and Senate.

Two vetoed bills, in particular, have taken center stage in the showdown.

One would cut the state’s income tax, which Republicans argue will help foster business within the state. In a campaign-style tour across the state over the past several months, Nixon has said the cut would leave the state unable to fund vital programs.

The bill phases in a 50 percent business income deduction over the next five years. It would also potentially reduce the individual income tax rate by .5 percent in increments over the next 10 years. The bill requires economic growth benchmarks to be achieved before each phase of the reduction in the state income tax rate can take place.

The bill’s sponsor, Rep. T.J. Berry, R-Kearney, said state government would look at the highest yearly revenue earnings of the past 3 years. If the state’s revenue in the current year is not $100 million more than the previous high, the deduction will be delayed that until the year that benchmark is reached.

Also on the agenda is a bill Republicans have dubbed the “Second Amendment Preservation Act.” The measure would declare several federal gun control laws void in Missouri and make it illegal to publish the name of any gun owner.

Republican lawmakers like House Speaker Tim Jones, R-Eureka, have touted the strength of the party’s veto-proof majority since the legislative session began in January.

Jones said Tuesday following his chamber’s GOP caucus he is still unsure of the fate of the income tax cut bill.

“We had 100 Republican votes during the session so picking up those last nine was always an uphill challenge,” Jones said. “It remains to be, but we will continue to work on what is a major priority for this caucus up until veto session.”

He also declined to say whether the House would have the necessary 109 votes for an override of the gun bill.

Senate President Pro Tem Tom Dempsey, R-St. Charles, said he believes the Senate has the votes to override the tax overhaul but said the Republican Caucus is still debating the gun law nullification bill due to legal concerns.