JEFFERSON CITY - Democratic Gov. Jay Nixon said Wednesday that he will not change the way he governs in his second term despite having to contend with veto-proof majorities in both legislative chambers of Missouri's General Assembly.

House Speaker Rep. Tim Jones, R-St. Louis County, issued a challenge to the governor Wednesday, saying Nixon would have to work better with the legislature than he has in the past. Jones said the governor would have to "make his agenda known and his opinions known on specific legislation" so lawmakers "can pass a bill one time and have it become law."

"The governor will need to understand the importance of true, actual negotiation during the legislative process as the 'checkmate' that he possesses, in the form of a veto, is now equaled by the overwhelming numbers that we have in the House and the Senate," Jones said.

When asked to respond to Jones' comment, Nixon said he does not approach his position in a partisan way and will "continue to work with members of both sides of the aisle."

"Being the chief executive of the state has many things that are broader or different than that, and they take a tremendous amount of energy," Nixon said in regards to working with the legislature.

In a campaign advertisement airing days before the election, Jones said "Jay Nixon doesn't work with Republicans and he's not independent."

Sen. Jolie Justus, D-Jackson County, also said Nixon "plays his cards close to his vest." Justus, who was selected as the new Senate Democratic Floor Leader Thursday, added that she has a good relationship with the governor and hopes to continue that relationship as the leader of the Senate's minority caucus.

During the press conference, Nixon discussed the issue of a state-based health exchange, where he said "the law is the law." States have until Nov. 16 to develop a plan for state-based exchanges. If the state is unable to proceed or refuses to implement an exchange, the federal Health and Human Services Department will move forward on a federally facilitated exchange. Nixon said his administration is unable to move on an exchange, as 62 percent of voters approved Proposition E, which constrained his authority to do so. Nixon also blamed the General Assembly for not moving forward on an exchange.

"Over the past two years, the General Assembly has shown an unwillingness to address the issue of exchanges," Nixon said.

The state House and Senate approved a bill to develop an exchange in the 2011 legislative session, but it never made it to Nixon's desk. Nixon said a federally-run exchange is not the ideal approach for Missouri, a position he did not assert before he won re-election.

"Regulating the insurance market is a power best left in the hands of the states," Nixon said at the press conference. "We can perform these duties more efficiently and effectively and provide better service for our consumers."

However, Nixon said the only option now for Missouri is to have the federal government run its exchange.

Nixon also addressed another provision of the Affordable Care Act, the decision whether or not to expand Medicaid. Nixon did not offer a position, and said it will depend on budget discussions and presentations over the next few months.

"The parameters are you want a healthier Missouri, you want to use taxpayer dollars as efficiently as possible, but you have to see quite frankly what happens with our federal partners over the next few months," Nixon said.