JEFFERSON CITY — Missouri Attorney General Chris Koster became the most prominent Democrat to endorse a proposed constitutional right to farm Wednesday, saying it could protect against arbitrary policies pushed by animal welfare activists.

Koster said the proposal on the Aug. 5 ballot is unlikely to affect existing regulations, such as those requiring buffers around buildings housing thousands of hogs, but could help head off future policies limiting the way farmers can raise livestock and crops.

He said it also could help farmers fight unreasonable uses of eminent domain to seize their property for developments.

Proposed Constitutional Amendment 1 states that the right "to engage in farming and ranching practices shall be forever guaranteed in this state."

"Under the amendment, future regulations of agriculture will be more closely scrutinized by the courts to ensure any restriction is related to a strong governmental interest," narrowly tailored and balanced against other personal rights, Koster said at a news conference at the Missouri Farm Bureau headquarters.

Koster's event came a day after Democratic Gov. Jay Nixon acknowledged that he is leaning toward opposing the amendment. Koster is running to succeed Nixon in the 2016 gubernatorial election.

The proposed amendment was referred to the ballot by the Republican-led Legislature, with the support of some Democrats, and has been endorsed by the Missouri State Republican Committee and most Republican elected officials.

As attorney general, Koster is responsible for defending challenges to state laws and regulations.

Opponents of the ballot measure have suggested it could be cited by corporate livestock farms to try to escape regulations on pollution and nuisances. They criticized Koster for supporting the measure.

"The effects of this ambiguous law are so broad, you would think that as Missouri's 'Lawyer in Chief' he would be more cautious with his support of a law that could tie up Missouri's court system and cost the state millions," said Joe Maxwell, a former Democratic lieutenant governor who now is vice president of outreach and engagement for The Humane Society of the United States.

Koster said he didn't think the amendment would affect most current regulations, because he said they are supported by strong governmental interests.

But Koster said the proposed constitutional amendment could prevent initiatives similar to one supported by the Humane Society in 2010. Among other things, that voter-approved measure imposed a limit of 50 breeding dogs per business. The limit later was repealed by the Legislature.

Koster, who supported other parts of that ballot measure, said the dog limit was an arbitrary restriction on the size of a business that would be damaging if applied in the future to hog or cattle operations.