<p class="title"> David Koch, a billionaire American libertarian and influential donor to conservative causes, has died at age 79 after a long battle with cancer, his brother Charles said on Friday.</p>.<p class="bodytext">Koch retired last year as executive vice president of Koch Industries, the conglomerate he co-owned with his older brother and built into the second-largest family-owned company in the United States.</p>.<p class="bodytext">"We wish for all to celebrate the life and impact of this most generous and kind man," Charles Koch said in a statement.</p>.<p class="bodytext">"He believed he had a responsibility to a world that had given him so many opportunities to succeed."</p>.<p class="bodytext">Both brothers were a force behind the scenes in Republican politics, donating heavily to candidates and causes that reflected their conservative economic positions.</p>.<p class="bodytext">But David was socially liberal -- a supporter of abortion rights and same-sex marriage as well as a non-interventionist foreign policy.</p>.<p class="bodytext">Both brothers were recognized in 2015 for bipartisan work on prison reform in the United States.</p>.<p class="bodytext">Among those offering condolences was Secretary of State Mike Pompeo who, like the Koch brothers, is from Kansas.</p>.<p class="bodytext">David Koch ran as the Libertarian Party's vice-presidential candidate in 1980, but later broke with it and swung to the Republicans.</p>.<p class="bodytext">He joined his brother Charles in financing a network of conservative organizations, in particular, Americans for Prosperity, centered on demands for low taxes and deregulation with the aim of influencing US elections.</p>.<p class="bodytext">Those organizations helped fuel the rise of the Tea Party movement in 2010, mounting a frontal Republican challenge to former Democratic President Barack Obama.</p>.<p class="bodytext">The Kochs' power was such that in the next presidential elections, Republican candidates vied for their endorsement, attending exclusive conferences the brothers organized.</p>.<p class="bodytext">Donald Trump, whose conservative credentials the brothers viewed with suspicion and who in turn often mocked them, was the exception.</p>.<p class="bodytext">Of the two, Charles has been most involved in the political networks while David had been more active in philanthropic endeavors, mainly in New York.</p>.<p class="bodytext">He was remembered as an important financial contributor to cultural organizations and medical research.</p>.<p class="bodytext">He was diagnosed with advanced prostate cancer 27 years ago but through "a combination of brilliant doctors, state-of-the-art medications and his own stubbornness kept cancer at bay," Charles said.</p>.<p class="bodytext">Born in Wichita, Kansas, Koch studied chemical engineering at the Massachusetts Institute of Technology before joining Koch Industries.</p>.<p class="bodytext">Forbes estimated his wealth at the end of his life at $42.4 billion, making him one of the world's richest people.</p>
<p class="title"> David Koch, a billionaire American libertarian and influential donor to conservative causes, has died at age 79 after a long battle with cancer, his brother Charles said on Friday.</p>.<p class="bodytext">Koch retired last year as executive vice president of Koch Industries, the conglomerate he co-owned with his older brother and built into the second-largest family-owned company in the United States.</p>.<p class="bodytext">"We wish for all to celebrate the life and impact of this most generous and kind man," Charles Koch said in a statement.</p>.<p class="bodytext">"He believed he had a responsibility to a world that had given him so many opportunities to succeed."</p>.<p class="bodytext">Both brothers were a force behind the scenes in Republican politics, donating heavily to candidates and causes that reflected their conservative economic positions.</p>.<p class="bodytext">But David was socially liberal -- a supporter of abortion rights and same-sex marriage as well as a non-interventionist foreign policy.</p>.<p class="bodytext">Both brothers were recognized in 2015 for bipartisan work on prison reform in the United States.</p>.<p class="bodytext">Among those offering condolences was Secretary of State Mike Pompeo who, like the Koch brothers, is from Kansas.</p>.<p class="bodytext">David Koch ran as the Libertarian Party's vice-presidential candidate in 1980, but later broke with it and swung to the Republicans.</p>.<p class="bodytext">He joined his brother Charles in financing a network of conservative organizations, in particular, Americans for Prosperity, centered on demands for low taxes and deregulation with the aim of influencing US elections.</p>.<p class="bodytext">Those organizations helped fuel the rise of the Tea Party movement in 2010, mounting a frontal Republican challenge to former Democratic President Barack Obama.</p>.<p class="bodytext">The Kochs' power was such that in the next presidential elections, Republican candidates vied for their endorsement, attending exclusive conferences the brothers organized.</p>.<p class="bodytext">Donald Trump, whose conservative credentials the brothers viewed with suspicion and who in turn often mocked them, was the exception.</p>.<p class="bodytext">Of the two, Charles has been most involved in the political networks while David had been more active in philanthropic endeavors, mainly in New York.</p>.<p class="bodytext">He was remembered as an important financial contributor to cultural organizations and medical research.</p>.<p class="bodytext">He was diagnosed with advanced prostate cancer 27 years ago but through "a combination of brilliant doctors, state-of-the-art medications and his own stubbornness kept cancer at bay," Charles said.</p>.<p class="bodytext">Born in Wichita, Kansas, Koch studied chemical engineering at the Massachusetts Institute of Technology before joining Koch Industries.</p>.<p class="bodytext">Forbes estimated his wealth at the end of his life at $42.4 billion, making him one of the world's richest people.</p>