As expected, Missouri Governor Jay Nixon (D) vetoed the Republican state legislature’s redistricting map Saturday, setting up a high-stakes showdown over the issue with just two weeks left in the statehouse session.

Nixon said the map — which would essentially eliminate the St. Louis-based 3rd congressional district held by Rep. Russ Carnahan (D) — did “not adequately protect the interests of all Missourians.”

The Missouri Constitution requires a two-thirds majority in both the House and Senate to override a veto. The redistricting bill, which was sent to the governor’s desk earlier this week, passed overwhelmingly in the Missouri Senate. It was approved by the House 96-55, a comfortable margin but 13 votes shy of the total that would be needed to override Nixon’s veto.

If the legislature cannot pass a redistricting plan, the courts could be left to draw the new legislative map.

“I am hopeful that in the next two weeks the Legislature can produce a map that will reflect a better representation for all regions of the state, and deliver it to my desk,” Nixon said in a statement.

2010 U.S. Census figures left Missouri with one less Congressional seat. The state’s delegation will drop to eight representatives following the 2012 election.