Just like the BP oil spill in the Gulf of Mexico last year put a stop to new oil drilling, nuclear problems in Japan are likely to end one of the few agreements between Republicans and Democrats in America's energy policy: nuclear energy.

The two sides had agreed in principle to build 20 new U.S. nuclear plants by 2030, but public anxiety now is likely to make new development politically unappealing.

Of course the traditional partisan lines may be difficult to draw. While the Obama administration claims it is still interested in new nuclear power development, Arizona Republican Sen. John McCain on Tuesday told a radio station he would consider additional evaluations.

"I'm not prepared by the way to say that we should abandon nuclear power because I think it's a major contributor (to) our energy needs, but I am prepared, once this is over, to make an evaluation as to whether our nuclear power plans can continue," McCain told KFI-550 in Phoenix.

Support for nuclear energy relies on three factors: First, it is green. Nuclear power has no carbon or greenhouse gas emissions. Second, it is domestic. There is no need to import nuclear energy the way other sources like oil are. Third, in the 30 years since the shutdown at Three-Mile Island near Harrisburg, Pa., nuclear has proven safe and effective.

So can the U.S. afford to take nuclear energy out of the equation? That depends on the political direction that prevails.

Huge discoveries of natural gas have made nuclear a more difficult sell than even three years ago. New nuclear plants do not pencil out as a worthwhile investment unless they are supported by taxpayer guarantees on the front end for bankers and on the back side for liability insurance.

By Tuesday morning, Standard & Poor's warned clients of a higher risk of plant cancellations and delays resulting from a disaster in Japan.

But most threatening of all to new development are perceptions of events in Japan.

"Worst case is a meltdown," said David Conover with the Bipartisan Policy Center. "Regardless of the actual physical consequences on the ground in Japan, the fact of a meltdown could result in a situation similar to what happened in this country after Three-Mile Island."

It is still unclear how events will unfold, but a few scenarios can be expected. Currently, the United States gets one-fifth of its electricity from 104 nuclear plants. A third of those facilities are 30 years old and are scheduled for shutdown and retirement unless they are granted a new 20-year license.

"Nuclear power currently accounts for about 20 percent of United States electricity and if you took that off the table, it would have a significant impact on our economy and quality of life," Conover said.

To meet the country's future power demands, the U.S. will need 20 new plants as well are the re-licensing of existing plants.

After the situation in Japan, energy companies can expect a more rigorous process to get old plants re-licensed, a possible suspension of the permitting process and an immediate review of existing plant redundancies. Construction of new plants may completely stop because of public perception and financing drying up as investors shy away from the uncertainty nuclear brings.

On Tuesday, White House spokesman Jay Carney noted that the Nuclear Regulatory Commission has a conditional loan for one construction project and several others are under consideration, but the licenses will be granted based on whether the plants are safe and secure, which is constantly re-evaluated.

Energy Secretary Steven Chu added in congressional testimony that the Obama administration stands by its belief the U.S. must rely on a diverse set of energy sources that includes renewable energy like wind and solar, natural gas, clean coal and nuclear power.

But Victor Gilinsky, a former Nuclear Regulatory Commission member, said the impact of Japan’s catastrophe on U.S. plans can’t be understated.

"I think we are going to have to think a little harder about the new plants," Galinsky said. "It is hard to overcome that picture."