As much fun as it might be to guffaw over Haig's misadventures while Ronald Reagan was near death in 1981, Lyn Nofziger, and the Times, have it wrong. Haig's most important role in history was as Richard Nixon's chief of staff as the presidency collapsed, and his most important contribution to that was his part in the Saturday Night Massacre, the event which essentially sealed Nixon's fate. The obit oddly portrays Haig as a passive victim of that episode, but in fact Haig was a major actor, and probably bears plenty of the responsibility for just how ugly it turned out to be.
The Washington Post, while accepting as the Times does Haig's self-aggrandizing and in my opinion very dubious version of Haig's benevolent role in Nixon's final days, has a somewhat more accurate version of the events prior to that:
When the public learned about the secret Oval Office taping system, which would eventually implicate Nixon in the coverup, Gen. Haig acknowledged later that he urged the president to destroy the tapes.
Of course, destroying the tapes would have been obstruction of justice. The Post also includes Haig's participation in the Kissinger taps, which the Times skips. However, neither mentions Haig's (possibly benign, possibly scary-bad) involvement in the Moorer-Radford affair.
When Watergate special prosecutor Archibald Cox, Jaworski's predecessor, pursued his investigation too aggressively for Nixon's comfort, the president dispatched Gen. Haig in October 1973 to instruct acting Attorney General William Ruckelshaus to fire Cox. "Your commander in chief has given you an order," Gen. Haig told him. Ruckelshaus refused, quitting instead in what became known as the Saturday Night Massacre.