JOAN LOWYWASHINGTON (AP) â¿¿ The Senate killed Republican-backed attempts to overturn several of President Barack Obama's environmental and energy policies Thursday as lawmakers worked against a March 31 deadline to keep aid flowing to more than 100,000 transportation construction projects around the country. The two-year, $109 billion transportation bill before the Senate has wide, bipartisan support, but has become a magnet for lawmakers' favorite causes and partisan gamesmanship. Among the amendments batted aside were GOP proposals to bypass Obama's concerns about the Keystone XL oil pipeline, to delay tougher air pollution standards for industrial boilers and to expand offshore oil drilling. Action on those and other amendments came under an agreement between Senate Majority Leader Harry Reid, D-Nev., and Minority Leader Mitch McConnell, R-Ky., aimed at clearing the way for passage of the transportation bill next week. Obama lobbied some Senate Democrats by telephone ahead of the Keystone vote, urging them to oppose an amendment by Sen. John Hoeven, R-N.D., that would have prevented the president from intervening in decisions related to construction of the pipeline and would have speeded its approval. Pointing to the administration's environmental concerns about the project, which would carry tar sands oil from Canada to the Texas Gulf Coast, Republicans accused Obama of standing in the way greater oil supplies at a time when Americans are coping with rising gasoline prices. But some Democrats, especially those from oil producing states, were torn between support for the pipeline and their support for the president. The amendment was defeated 56-42, even though 11 Democrats broke ranks to support it. Sixty votes were needed for passage. Republican leaders jumped on the White House lobbying. "Most Americans strongly support building this pipeline and the jobs that would come with it," McConnell said in a statement. The president's lobbying against the Keystone provision came "a week after the president signaled to me and to Sen. McConnell that he might be willing to work with us on some bipartisan steps forward on energy legislation that the American people support," House Speaker John Boehner, R-Ohio, told reporters. "If we're going to have bipartisan action on energy, the Keystone pipeline is an obvious place to start."