WASHINGTON -- Long-awaited climate change legislation was put on hold by its authors Saturday when a dispute over immigration politics and Senate priorities threatened to unravel a bipartisan effort that took months of work.

Voicing regrets, Sen. John Kerry said Saturday he is postponing the much anticipated unveiling of comprehensive energy and climate change legislation scheduled for Monday. The Massachusetts Democrat made his announcement after a key partner in drafting the bill, Republican Sen. Lindsey Graham of South Carolina, threatened to withhold support if Senate Democratic leaders push ahead first with an immigration bill.

Graham is angry that Majority Leader Harry Reid of Nevada is considering that. Legislation to overhaul immigration laws and grant legal status to millions of long term immigrants unlawfully in the country could create problems for Republicans in the midterm elections. It's a top priority for Hispanic voters -- and most Republicans are opposed. Reid's idea amounts to a "cynical political ploy," Graham asserted.

Kerry tried to assure environmentalists and other backers of the climate bill that the delay will be short. The legislation aims to cut emissions of pollution-causing greenhouse gases 17 percent below 2005 levels by 2020. It also likely will expand domestic production of oil, natural gasand nuclear power.

"We all believe that this year is our best and perhaps last chance for Congress to pass a comprehensive approach," Kerry said in a statement. "Regrettably, external issues have arisen that force us to postpone only temporarily."

Kerry, Graham and Connecticut independent Sen. Joe Lieberman have spent more than six months working on the bill they had hoped to unveil Monday. White House energy adviser Carol Browner praised the three senators, reiterating that the Obama administration wants the energy and climate bill done this year.

Graham's threat to back away from the coalition came Saturday in a letter to Senate leaders.
He said putting immigration at the top of the legislative priority list would derail efforts to find common ground on climate change, a difficult issue involving critically important economic priorities. And he warned that Republican lawmakers would not take kindly to being put on the spot with Hispanics. Many in the Republican Party's political base are adamantly opposed to 'amnesty' for illegal immigrants.

"Moving forward on immigration -- in this hurried, panicked manner -- is nothing more than a cynical political ploy," Graham said. "Let's be clear, a phony, political effort on immigration today accomplishes nothing but making it exponentially more difficult to address in a serious, comprehensive manner in the future."

Kerry praised Graham's work on the climate legislation, saying the Republican "helped to build an unprecendented coalition of stakeholders from the environmentalcommunity and the industry who have been prepared to stand together behind a proposal."

He and Lieberman "deeply regret that (Graham) feels immigration politics have gotten in the way and for now prevent him from being engaged in the way he intended," Kerry said.

Pushing immigration ahead of climate legislation would disappoint and anger environmentalists, who see this as their best chance in recent years to pass a bill addressing global warming. But Reid told fellow Democrats this week he wants to pursue legislation that would offer legal status to many unlawful immigrants before tackling climate change.

Hispanics voted heavily Democratic in 2008, and they've been disappointed with President Barack Obama and congressional Democrats for not following up on campaign promises to reform immigration laws. Reid is up for re-election this year and trailing in polls in Nevada, where Latinos are an important constituency. With Democrats facing a tough political climate in the midterm elections, energized Hispanic voters could make a difference in several states.

In a statement Saturday that was both conciliatory and noncommittal, Reid said he is committed to passing both immigration and energy this year.

"Immigration and energy reform are equally vital to our economic and national securityand have been ignored for far too long," he said.

Both measures will require bipartisan support, Reid said, "and energy could be next if it's ready." Comprehensive immigration reform requires significant committee work that has not yet begun, he noted.

Reid said he appreciates Graham's work on both issues, but added: "I will not allow him to play one issue off of another, and neither will the American people. They expect us to do both, and they will not accept the notion that trying to act on one is an excuse for not acting on the other."
A spokesman said Reid would continue to consult with Kerry on building bipartisan support for a climate bill.

The House last year narrowly passed a bill creating a systemto cap emissions blamed for global warming, but has not acted on immigration. House Speaker Nancy Pelosi has long said the Senate must vote before the House on an immigration bill.