The president must not be aware of the so-called “Medicare trigger” because, for the fourth year in a row, he’s ignored it. By law, if the trustees of Medicare issue a warning that the program faces insolvency, the president must submit a legislative proposal to reform the entitlement program no later than 15 days after he submits his budget.

Specifically, the law mandates that the Medicare Trustees issue the warning when, for two consecutive years, they determine that general revenues will account for more than 45 percent of Medicare’s outlays for the current fiscal year or any of the next six fiscal years. In other words, when the Medicare trust fund will cover no more than 55 percent of the program in an upcoming fiscal year, the Trustees are bound by law to warn the president and the president is bound by law to respond to the warning with a plan for reform.

The Trustees issued just such a warning in their last report (the fifth consecutive year they’ve attempted to trigger reform), but the president has not responded to the warning (the fourth consecutive year he’s ignored it). The deadline was Tuesday at midnight.

House Budget Chairman Paul Ryan and Senate Budget Committee Ranking Member Jeff Sessions aren’t happy about the president’s negligence and sent a letter to him to demand his proposal. Given that he’s willing to ignore the law, it’s doubtful a letter will compel the president to act — but, at the very least, it should help to call attention to the president’s lack of seriousness on this issue.

Why won’t Barack Obama put forth a Medicare proposal? Simple. If he does, Democrats lose the opportunity to demagogue the issue in the run-up to the 2012 election. Paul Ryan’s premium support plan to reform Medicare would actually save and strengthen Medicare — yet, in at least one special election, Democrats managed to convince seniors that Ryan is the pol who wants to push granny off a cliff. They’re hoping to convince seniors of the same in the 2012 presidential election.

In reality, the president’s decision to do nothing to reform Medicare is a default decision to destroy Medicare — or, rather, to allow it to destroy itself. At least one Democrat — that would be Sen. Ron Wyden — has realized this and has partnered with Ryan to promote a premium support plan alongside traditional Medicare. The Ryan-Wyden plan is a less palatable compromise than Ryan’s original plan, but it’s better than nothing. Predictably, Wyden took heat for his willingness to team with Ryan.

Still, Ryan’s not giving up on the issue; he convinced all the GOP contenders to stand by his plan (even Newt Gingrich reversed his controversial comment that the Ryan plan is “right-wing social engineering”) and he’s slowly building a bipartisan coalition to promote it, too. A handful of Democrats have anonymously admitted they like it — but are afraid to openly support  it until after the election.

Those of us who know that entitlement programs are the key drivers of our debt have a responsibility to spread the facts — and to back up politicians who stick their necks out for bold solutions. They’ve got to know we support them — and the president needs to learn we see through him. We won’t believe he cares about seniors or the social safety net until he proves that he cares about seniors and the social safety net — by putting forward a plan to save Medicare.