Last Thursday morning, a huge crowd of reporters breathlessly covered presumptive Republican nominee Donald Trump's meeting with House Speaker Paul Ryan. But the real action took place the day before the meeting -- and the person who "caved" wasn't Ryan, but Trump.

In his quest for the Republican nomination, Donald Trump has attacked Hispanics and Muslims. Now that he is pivoting to the general election, seeking campaign contributions from wealthy donors and endorsements from the Republican establishment, he is signaling his willingness to go after working families.

To anyone who watched a Republican debate or one of Trump's rallies, he unabashedly proclaimed that he would not cut Social Security. Indeed, he explicitly contrasted himself with the other Republican Presidential contenders (all of whom, except for Mike Huckabee, support benefit cuts). Given that only 17 percent of Republican voters support Social Security cuts, this was an important part of Trump's populist message and likely a major reason for his victory.

Now that Trump has clinched the nomination and is seeking money from the GOP's big donors, and support from the party's establishment, however, he has changed his mind -- or at least his position. (Who knows what he really thinks?)

Social Security has been a target of the Republican Party from the moment the legislation was introduced in 1935. It passed the House of Representatives essentially on a party line vote. (The telling vote was a procedural vote to kill it immediately before final passage.) In the 1936 presidential election, the Republican standard bearer, Alf Landon, vowed to repeal it if elected.

In 1953, Republicans unsuccessfully tried to convince the newly elected Dwight Eisenhower to dismantle the program. (In a 1954 private letter to his brother, Eisenhower wrote about those who want to abolish Social Security, "Their number is negligible and they are stupid.")

The late Republican presidential nominee and Senator, Barry Goldwater, was anti-Social Security, as was the late President Ronald Reagan, at least before he became president. And, of course, President George W. Bush sought to privatize Social Security.

Revealingly, in a memorandum marked "not for attribution," but nevertheless leaked, President Bush's director of strategic initiatives wrote about the effort to dismantle Social Security, "this will be one of the most important conservative undertakings of modern times." He concluded, "For the first time in six decades, the Social Security battle is one we can win."

Paul Ryan and his zeal for cutting Social Security is in line with his Party's history. Since he was elected to the House of Representatives in 1998, these cuts have been his top priority. In 2004, Ryan pushed a plan to privatize Social Security so extreme that even George W. Bush called it "irresponsible." In 2007, Ryan became the ranking member of the House Budget Committee, and used that perch, as well as his subsequent position as Chairman, to draft yearly budgets that included massive cuts to Social Security, Medicare, and Medicaid. (In recent years, he has become a bit more politically savvy, proposing a fast-track process to force through cuts, without specifics, but his intent is certainly clear to anyone who follows the issue.)

Ryan could not be happy that Trump pledged not to go after Social Security. Who would blink? Turns out that for all his bravado and bullying, it was Mr. Trump. He chose the perfect forum, the day before his meeting with Ryan.

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.

The good news is, voters will have an alternative choice in November. Both Democratic candidates are strongly in support of expanding, not cutting, Social Security. That's is wise policy as well as winning politics. It is the position favored by 72 percent of the American people -- and one that Trump has never supported. The same contrast can be seen at the Congressional level. 75 percent of House Democrats and 90 percent of Democratic Senators support expanding, not cutting, Social Security, while virtually no Republicans do.

In recent elections, the Democratic presidential candidates have lost the votes of seniors. Probably not coincidentally, in recent elections, seniors could not tell who stood with them on the bread and butter issue of Social Security. All candidates talked about "saving" Social Security and the need for a bipartisan solution.

This election, as long as the Democratic presidential nominee runs strong, loud, and clear, on expanding, not cutting Social Security, and revealing how untrustworthy Donald Trump is on the issue, Democrats should once again win the senior vote. And with it, the White House, the Senate, and perhaps even the House of Representatives. Stay tuned!