Why is Reagan so idealized, often compared to Lincoln?
Like others have said, there are no other Republican President in recent memory who had a positive impact on the country by helping the Soviet Union crumble itself ultimately making the US as the only Super Power left on the planet. Plus he established the ideology of the Republican party as it stands today with the concept of supply-side or trickle-down economics (derided by the other side) and the whole concept of small government (never mind that no one follows it). Ranking presidents is a matter of the era in which one lives. Based on contemporary wisdom, people look back and decide how a president influenced the country and whether they were positive. In the process, a lot of negatives are also brushed aside if they were not of direct long-term consequences. For example, Bill Clinton was a scandal in 1996 and Americans were ashamed that he was in the White house but the overall state of the economy and the jobs situation (not entirely of his making) makes him a well loved and successful president today especially after the disastrous period in the 2000s. Similarly even Lincoln was despised during his time, but the legacy he left for us makes him a great president. So, too for Reagan, despite all his corruption, his supply side economics, and his lack of attention to detail sometimes (there were embarrassing photos of him sleeping on the stage during events), he is credited with bringing the Soviet Union down. Although it was Gorbachev who did most of the heavy lifting, he did help with his Star Wars plan etc (it is not clear whether it was intended as a strategy to bring them down or whether as a Hollywood hero, he really believed in it). In general, a President who brought about a major change, be it Lincoln, Reagan, Johnson (Medicare, Civil Rights) will be remembered if that change was for the good of the people. In that vein, we never know if Obama will be praised or vilified for ACA. We will need to wait another 30-40 years for that verdict.
What would happen if scientists proved that God does not exist?
this question has important anomalies which are needed to be understood. God as a concept comes from religions and Science is not a religion. Science started from observation . Body of science grew from testing and verifying those observations. As a body of knowledge science does not deal with issues of life after death, morality , purpose of life and human beings , matters of inheritance etc. Religions answer these questions. You can not put them to test. How should i behave with my mother and father, how my inheritance should be divided and how should i behave with people in the society cannot be put to scientific way of testing or prove or disprove type results. I cannot knock the doors of science to answer such questions. Weather or not i agree or disagree with answers provided by religions but one thing is for sure religions are there from thousands of years. They have told human beings very important things such as : not marry their mothers , sisters to grow families. Behave nicely with people . Religions have established grounds for morality. Science has different role to play in the society. The way you can not ask religion to prove or disprove scientific theories , the same way you cannot ask science to answer religious concepts. The same way you cannot ask science to interpret the religious injunctions . I am not saying that people should not challenge the concept of God. But challenging the concept of God with crutches of science wont help. It is simply like asking an I.T question from a food expert. There are very complex questions that are there but answering them from scientific perspective are not possible. We all know we have emotions of infatuation , hatred , narcissism, bias, protection , respect , generosity , tolerance , compassion etc. But did we need science to first prove them and then admit their existence. There is so much in this world that exists and its existence does not need the crutches of science to prove them. Science has a different domain and it has its own set of questions to deal with . God and religion belong to other domain and there are different sources of knowledge that exist which help answer the questions about God.