Republicans hope today’s rollout of a plan by Senate GOP Conference Chairman Lamar Alexander (Tenn.) and his House counterpart, Rep. Mike Pence (Ind.), to build more nuclear reactors will mark the beginning of a new era of greater cooperation between Republicans on either side of the Capitol at a time when their party is struggling to find a unified voice.

Since the November elections, Republicans have repeatedly stressed the need for better coordination between the House and Senate conferences, particularly since they are not only the minority in both chambers, but also because they no longer have the bully pulpit of the presidency.

Their diminished power, combined with the prominence of Republicans such as Alaska Gov. Sarah Palin, former Speaker Newt Gingrich (Ga.) and radio personality Rush Limbaugh, has often left the party with a fractured voice. And it has occasionally marginalized Congressional Republicans, whose difficulties developing consistent policy positions are sometimes exacerbated by the electoral pressures that Members face.

The two chambers have frequently been able to coordinate their message — most notably during the budget debate and the recent fight over President Barack Obama’s desire to close the Guantánamo Bay prison. Republicans have “had a lot of success with message— on these issues, Pence spokesman Matt Lloyd said. Lloyd noted that those successes “were dependent on both sides of the Capitol having the same message.—

But while agreement over policy proposals has been much harder to come by for Republicans, Alexander and others said they hope that is beginning to change.

“I can’t remember a time when we’ve been as unified as we are on such an important message … a message that presents a distinction between Republicans and Democrats,— Alexander said last week.

The new political landscape means that Republicans have had to shift their efforts away from supporting a president’s agenda or setting the agenda for Congress to finding their openings in the agenda set by Obama and House and Senate Democrats.

“It’s like playing basketball. We have to let the game come to us. … As they set the agenda, we can then demonstrate how we want the country to go,— Alexander explained.

The nuclear power proposal that Pence and Alexander are rolling out today is fairly simple — they are calling for the construction of some 100 new power plants over the next two decades as a way to combat climate change while creating thousands of new jobs.

The nuclear power proposal is the centerpiece of a broader clean energy plan Republicans will be pushing over the next several months to combat the Democrats’ cap-and-trade climate change plan.

For months, Alexander and Pence have worked to put together a unified policy and message agenda on the nuclear issue as one of the GOP’s marquee energy platforms. According to Republicans, the two lawmakers were aided by the fact that over the past several years, Alexander has done a good job of convincing his colleagues that even if they do not believe climate change exists, it is a real political issue that must be addressed.

“There’s still a wide variety of opinions on climate change within our caucus. But nuclear power is also about low-cost electricity— and jobs, Alexander argued.

Additionally, Alexander and Pence have made a point to stress the need for massive new investments in the nuclear industry to not only combat climate change but to create jobs.

“Over the last several months, Republicans have worked on an energy message that’s pro-jobs, pro-energy and pro-environment,— Senate Republican Conference Staff Director Ryan Loskarn said. “The nuclear push meets all those criteria and has emerged just as Democrats begin pushing their national energy tax cap-and-trade legislation.—

A senior GOP aide said the unity demonstrated on nuclear energy — as well as on the larger climate change counterproposal from Republicans — is the result of Republicans being determined to offer substantive policy proposals, rather than simply standing in opposition to Obama administration plans.

“We’ve actually got issues now. … We actually have some policy position that we believe can be better alternatives,— the aide said.

“We see a Republican agenda emerging as the issues arise,— Alexander said, and further bicameral cooperation will likely be seen on the debate over housing policy as well as some aspects of the coming debate over health care reform.