One reason New Mexico has such a vital Green Party is the Democrats often are indistinguishable from the Republicans when environmental issues are opposed by business interests.

Take urban sprawl. The 2003 Legislature passed and Gov. Bill Richardson signed a bill that puts a leash on Albuquerque’s zoning powers. It amended the city out of the extraterritorial zoning law under which combined city-county boards govern development in a five-mile-wide margin around city limits.

The bill was supported by the Albuquerque Chamber of Commerce and other business groups complaining that the mayor and city council majority were restraining economic development with their Planned Growth Strategy. A companion bill diluted the city’s power over its water system.

The bill was introduced by the state Senate majority leader, Manny Aragon, D-Albuquerque. Richardson anguished over signing it, as well he might because it was ardently opposed by the usual Democratic constituency of anti-urban-sprawl environmentalists, including 1,000 Friends of New Mexico.

Mayor Martin Chavez said of the new law: “I can’t imagine anything more hurtful to Albuquerque.” It had to be hurtful, too, for the Democratic mayor to get slammed by the Democratic governor.

Richardson submitted an op-ed explanation that he was only trying to get the city and county to talk to each other. But the politics was more interesting than the reasons. Richardson owed a great deal to Aragon for cooperation during the new governor’s maiden legislative session, and the Albuquerque business community had an obvious influence. And it was not just a local situation. The larger political meaning is that the Democrats and Republicans merged in opposition to extraterritorial zoning.

The Aragon zoning bill almost passed with an amendment to include two other sprawling cities, Santa Fe and Las Cruces. The amendment, approved by the Senate but removed by the House, was by another Democratic state senator, Santa Fe real estate agent Roman Maes. His rhetoric against the Santa Fe City Council was more vitriolic than the attacks on the Albuquerque mayor and council majority.

Maes, who votes like a Republican on business issues, took the floor of the Senate to argue that the Santa Fe government had lost support of the people with its “living wage” proposal and its restraint against high-density subdividing and that the situation was “dangerous.” In effect the senator was attempting to overturn a government he considered illegitimate.

It’s instructive that Sen. Ramsay Gorham of Albuquerque was part of the 8-0 Senate Conservation Committee vote that started Aragon’s zoning bill on its way. She has just been elected chairman of the state Republican Party in an acrimonious and expensive contest that ousted eight-year chairman John Dendahl of Santa Fe.

Gorham has a record of working with Aragon. One of her first legislative accomplishments, bringing more poor children under Medicaid, and one of her most publicized bills, to repeal the gross receipts tax on food, were done in partnership with Senate leader.

Now Aragon is one politician you’d never find embedded with Dendahl, who along with former Gov. Gary Johnson was ruthless in hounding not only the entrenched Democratic leaders of the legislature but also Republicans who collaborated with them.

Dendahl hinted at Gorham’s collaborative inclinations when he told the Republican Central Committee: “Unlike my opponent, I am prepared to shout ‘No!’ to Bill Richardson’s raid on the Permanent Fund.”

The reference was the governor’s plan to finance the teacher pay hike without raising taxes. It will require voter approval of a constitutional amendment in September allowing further drawdown of the state’s unusual endowment. Asked later if the party would carry out Dendahl’s planned campaign against the fund-diverting amendment, Gorham said she would have to wait and see if there was enough money.

Aragon hasn’t changed. He has constantly introduced bills opposing the authority of Albuquerque, which looms over his rural South Valley district. But he might be the middle term in the new political syllogism — the key to what might be happening in the post Dendah-Johnson era as the parties change back to the way they always have been in New Mexico.

In the atmosphere of political warming, Republicans and Democrats are dropping the pretence of being polarized on issues supported by business interests.