During the primary campaign, Donald Trump assured the voters that he would not cut Social Security or Medicare. He did that because even most of the Republican base doesn't want those cuts. But he has the nomination now, and to get support from GOP leaders he has flip-flopped on the issue. Those leaders have never liked Social Security or Medicare, because they are beholden to the rich (who fund their campaigns). They have repeatedly tried to hurt or eliminate both programs.
In the last part of May, Trump assured those leaders (and their rich benefactors) that he would be open to cutting both programs. Here is part of a Huffington Post article about Trump's betrayal of American seniors:
Pete Peterson is a Wall Street billionaire who has spent over 30 years and more than half a billion dollars on a crusade to cut Social Security. As part of that quest, he holds yearly “Fiscal Summits” where politicians and wealthy elites schmooze while nodding their heads about the non-existent debt crisis and the supposed “need” to cut earned benefits. This year, Sam Clovis, Trump’s top policy advisor, attended the Peterson Summit. And what he had to say was music to the ears of the well-heeled conference-goers: A Trump administration would be open to cuts in Social Security and Medicare. The timing and location of this statement was no accident. Clovis’s remarks took place in a room full of wealthy GOP donors, the day before Trump’s much-anticipated meeting with Speaker Ryan. Trump’s broken pledge reassured the GOP establishment that he was falling into line with right-wing orthodoxy. To those who have carefully studied Trump’s record on Social Security, this seemingly abrupt turnaround does not come as a huge surprise. Back in 2000, Trump wrote a book in which he referred to Social Security as a “Ponzi scheme”, proposed increasing the retirement age to 70, and claimed, “Privatization would be good for all of us.” As recently as 2011, he said he was on board with plans to cut Social Security, Medicare, and Medicaid — but that Republicans should be very careful “not to fall into the Democratic trap” by doing it without bipartisan support, or they would pay the price politically. Trump’s position on Social Security appears to be whatever he feels is most beneficial to Donald Trump at any given time. For that reason, it’s quite possible that now that he’s reassured Ryan and the GOP establishment, Trump will be doing yet another about-face soon. His actions in the primary show that he understands that Social Security cuts are politically toxic. That math is even clearer in the general election, where only 10 percent of Americans support cuts. But Trump has made it perfectly clear to anyone who might have lingering doubts that whatever he might say in the future, he can’t be trusted as a guardian of Social Security. He is on the side of Paul Ryan, Pete Peterson, and the billionaire class — and against the American people. This is just one more reason, among many, why it's imperative to vote Democratic in November.