Since the election of a Catholic President in 1960, Catholics have split about 50–50 between the two major parties in national elections. With the decline of unions and big city machines, and with upward mobility into the middle classes, Catholics have drifted away from liberalism and toward conservatism on economic issues (such as taxes). Since the end of the Cold War, their strong anti-Communism has faded in importance. On social issues the Catholic Church takes strong positions against abortion and same-sex marriage and has formed coalitions with Protestant evangelicals. In 2015 Pope Francis declared that man-made climate change is caused by burning fossil fuels. The Pope stated the warming of the planet is rooted in "a throwaway culture" and the developed world's indifference to the destruction of the planet as it pursues short-term economic gains. However, the Pope's statements on climate change were generally met with indifference among Catholics while Catholic commentaries ranged from praise to dismissal, with some stating that it was not binding or magisterial due to its scientific nature. The Pope's statements on these issues were most prominently laid out in encyclical "Laudato si"'. The publication by Francis had put pressure on Catholics seeking the Republican Party nomination for president of the United States in 2016, including Jeb Bush and Rick Santorum, who "have questioned or denied the established science of human-caused climate change, and have harshly criticized policies designed to tax or regulate the burning of fossil fuels."