Pipeline Politics, Economics and Science Re "Poisoned Politics of Keystone XL," by Joe Nocera (column, Feb. 7): Every pro-Keystone argument leaves out the same major facts: ¶Tar sands oil is not intended for United States consumption, but for shipping to the highest bidder. ¶The job projections were discovered to be highly inflated; State Department estimates barely break 5,000. ¶Many Canadians oppose a tar sands pipeline as it is destroying large sections of their environment. Mix this with about a dozen leaks that Keystone I has had in a single year, extremely high refining costs, and a route that puts American food and water supplies at increased risk, and it's hard to find a reason to like Keystone XL. If Americans want to outgun China, it's not going to be on the back of dirty oil, but on renewable energy and ingenuity. Although Joe Nocera is probably right to lay most of the blame for the Keystone pipeline fiasco on our intractable political situation, President Obama is supposed to be the grown-up in the room. But instead of seizing the opportunity to improve American energy security and reduce the 17-plus percent unemployment rate in the construction trades, his dissembling is pushing Canada into the arms of the Chinese. Blocking the Keystone project will not reduce American dependence on imported oil, preclude development of Canada's oil sands, or have any meaningful impact on climate change. What it will do is squander the benefits of having huge oil reserves just across the border under the control of a true and trusted ally and put the seas at risk from the supertankers that will carry that oil to Asia. That's flawed policy on both security and environmental grounds. The writer is a senior fellow at the Price School of Public Policy at the University of Southern California. Joe Nocera states that opposing the expansion of tar sands oil is "ludicrous." Not if you're rational enough to believe in science. The reality is that we must decrease global emissions - deeply, rapidly and permanently - to avoid potentially vast environmental and economic disruption. The only way to avoid dangerous, irreversible climate change is by reducing fossil fuel dependence at every opportunity, not by investing billions in new fossil fuel development. Keystone opponents are arguing that we accept climate science and act responsibly on what we know. To do otherwise would truly be ludicrous. JABE BLUMENTHAL Board Co-chairman Climate Solutions Seattle, Feb. 8, 2012 Bravo, Joe Nocera. He presented this issue as it really is. In particular, he makes clear that President Obama's decision to reject TransCanada's application had nothing to do with either energy or environmental concerns but was based entirely on electoral politics. Which is not to say that the Republicans handled the issue responsibly, as he also points out. Let us hope that after November we can move ahead with this essential project. The writer served as ambassador to Canada from 1985 to 1989 and is vice chairman of the United States Council for International Business.