Energy has become a crucial issue in the 2012 US presidential and congressional campaigns.
For all the time being spent discussing energy issues however, neither campaign is being completely honest about the choices ahead.
Presiden Obama emphasises his support for a comprehensive strategy that embraces all potential sources of energy. But he remains reluctant to admit that emissions-creating fossil fuels will still play a major role - a fact many of his most ardent supporters in the environmental movement find uncomfortable.
Romney's campaign is more open about the need for more exploration and drilling but does not seem to have any idea about how to promote renewables or curb greenhouse-causing emissions.
It would be nice to think some of these difficult choices will be explored on the campaign trail before the voters have to make their final choice. But a degree of ambiguity is useful to both campaigns, which suggests voters will be left in the dark about what either candidate would actually do on crucial aspects of energy policy.
Speaking in New Mexico on Thursday, Romney promised to make energy independence for North America by 2020 a national goal.
To achieve it, the Republican outlined a five-point program including giving responsibility for issuing drilling permits on federal lands to state governments to cut delays as well as a five-year leasing programme for offshore exploration including off the coasts of the Carolinas, Virginia and the US Gulf.
Romney also promised to create an energy partnership with Canada and Mexico to fast-track the approval of infrastructure, starting with the controversial Keystone XL oil pipeline; an accurate inventory of national energy resources; and changes in regulatory processes to ensure energy projects are approved where needed and that the process is not used to stop energy production.
The Romney campaign has framed energy squarely as an economic issue. Energy independence features prominently as the first element in Romney's "plan for a stronger middle class", which promises to secure more jobs and more take-home pay.
In contrast, the Obama campaign twins energy issues with the environment. The president's website emphasises his administration has made protecting the environment a priority, while insisting his "all of the above" strategy means "never having to choose between protecting our environment and strengthening our economy."
Obama's campaign claims policies to promote investment in clean energy "have helped create hundreds of thousands of job." Investment in clean technology is promoted as a way to spur a high-tech manufacturing revolution.
Both campaigns are keen to highlight their energy policies (though Republicans seem markedly more enthusiastic than Democrats). But neither side is entirely comfortable talking about the subject, and both prefer to keep quiet about some of the difficult tradeoffs it presents.
The Romney campaign wants to focus on the potential for increased oil and gas production to boost the economy and national security, if only the federal government would step out of the way.
For Romney, energy policy unifies all aspects of the Republican base: pro-business groups, small-government conservatives and the national security lobby. It usefully divides Democrats, pitting environmentalists against unions and workers in energy-intensive sectors such as steel, cement, coal and transport.
Divisions within the Democratic Party were on display when large numbers of legislators from coal and industrial states voted against emission curbs and again when many Democrats from oil and gas-producing states and conservative-leaning districts rebelled against the president's decision to block Keystone.
But the Romney campaign is less candid about what producing all this extra oil and gas would mean for global warming. It would almost certainly leave clean energy technologies such as wind and solar struggling to compete, especially since Romney has pledged to oppose the renewal of subsidies, and Republicans remain hostile to cap and trade and other forms of carbon pricing.
What about coal?
If Romney is not presenting the whole picture, neither is Obama.
The president has been silent on the future role of coal, which is one of the biggest sources of fossil energy and the largest part of the country's reserve base.
The Energy Department is supporting research and pilot projects into a broad range of technologies based around gasification as well as carbon capture utilisation and storage (CCUS). The problem is that none is anywhere near ready for commercialisation, let alone roll-out on a national scale.
Without them, however, it is not clear what future the administration sees for the coal industry and coal-fired power plants.
Obama's Environmental Protection Agency (EPA) has proposed rules that would bar the construction of new coal-fired plants beyond 2014. But coal is a massive part of existing installed generation and the country's energy reserves. It is also vital to the economies of several states. Trying to phase out coal use is impractical.
Don't mention Keystone
The president is even more quiet on Keystone. Having refused to grant a presidential permit for the northern leg of the pipeline earlier this year on narrow and procedural grounds, the president has left both sides hopeful of an eventual victory after the election is over.
If re-elected, however, he is going to have to disappoint someone. Environmentalists have invested enormous significance in Keystone and are among the president's most enthusiastic and committed supporters. If the pipeline is eventually approved, many will feel betrayed.
But pipeline supporters have also been led to believe that the administration will eventually come down on their side. The White House has indicated it is not hostile to the pipeline in principal and that its objections relate to just a small section of the line in Nebraska, which should be overcome with just a little more work and consultation.
If approval is eventually withheld, much of the oil and gas industry, as well as many lawmakers and the Canadian government, would see it as a broader attack on fossil fuel development and on proposals to supply more oil and gas from western Canada.
This article was originally published by Reuters. Republished with permission.