Changes in Trump's campaign positions have pleased critics but upset some supporters. However, Trump has a history of altering his stances during the campaign, so it is possible that the president-elect could change his positions again before or after he is inaugurated on Jan 20. One example of this is his stance on prosecuting Hillary Clinton, as he initially promised to do so during his campaign but later stated that he wanted to move forward and not dwell on the issue. He stated that he does not wish to cause harm to the Clintons. Despite this, he did not completely rule out the possibility of investigating Clinton. Trump has denied the reality of climate change and expressed intentions to pull out of the 2015 Paris Agreement, opting instead to focus on utilizing inexpensive coal, shale, and oil. A source from Trump's transition team stated on November 12 that his advisers were exploring options to circumvent the four-year process for exiting the climate accord. In an interview with the Times on November 22, when asked about America's role in addressing climate change, Trump mentioned having an open mind and stated that they would be examining the situation closely. When asked about his beliefs regarding human activity causing climate change, he mentioned a potential connection but was not definitive. It all depends on the quantity. During his campaign, Trump stated his intention to repeal the Affordable Care Act implemented by President Barack Obama, which he referred to as a "disaster." He proposed replacing it with a plan that would grant states more control over the Medicaid health plan for low-income individuals and permit insurers to offer plans nationwide. Trump mentioned in an interview with the Wall Street Journal on Nov 11 that he was contemplating retaining certain aspects of the law, such as allowing parents to keep adult children up to age 26 on their insurance policies and prohibiting insurers from refusing coverage to individuals with pre-existing conditions. Trump informed the Journal that either Obamacare would be revised or completely replaced. During his campaign, Trump promised to build a wall on the US-Mexican border to reduce illegal immigration and have Mexico pay for it. He also pledged to deport millions of illegal immigrants and suggested a temporary ban on Muslims to address terrorism concerns. Towards the end of the campaign, he modified his stance to propose a temporary suspension of immigration from regions associated with terrorism and lacking secure vetting processes. Trump confirmed his intention to build a wall in an interview with CBS' "60 Minutes," mentioning it could be a combination of wall and fence. He mentioned that he would prefer a fence for certain areas and a wall for others, stating that he is skilled in construction. When asked about deporting illegal immigrants, he stated that the focus would be on those with criminal records, estimating that there are possibly 2 to 3 million such immigrants. Trump also expressed his support for the use of waterboarding and other harsh interrogation tactics for terrorism suspects, despite it being considered torture and banned under President Obama. In an interview with the New York Times on November 22, Trump mentioned being impressed by Marine General James Mattis' response to a question about waterboarding. Mattis stated that he performs better with a pack of cigarettes and a couple of beers than with torture. Although Trump's opinion on waterboarding remained unchanged, he was impressed by Mattis' belief that it may not be as effective as some people think.