Dropping out in March? No wonder my dad was stunned when he got on the TV about it. You’d think he would have risked losing a few primaries first before bugging out, just like Bush in 92. That’s a bit worse than McCain suspending his campaign during the last election. I don’t think Obama’s at that point yet.
LBJ's withdrawal was earlier in the process than you would think.
Only one primary had been held -- New Hampshire, on March 12. And LBJ actually won it (49/42 over Eugene McCarthy).
However, on March 16, Bobby Kennedy announced his candidacy...and LBJ knew he was done for.
Only twelve states held primaries that year. It was a different political landscape...
Some history.
http://en.wikipedia.org/wiki/Democratic_Party_presidential_primaries,_1968
Despite the growing opposition to Johnson’s policies in Vietnam, no prominent Democratic candidate was prepared to run against a sitting President of his own party. Even Senator Robert F. Kennedy of New York, an outspoken critic of Johnson’s policies with a large base of support, refused to run against Johnson in the primaries. Only Senator Eugene McCarthy of Minnesota proved willing to openly challenge Johnson. Running as an anti-war candidate in the New Hampshire primary, McCarthy hoped to pressure the Democrats into publicly opposing the Vietnam War. Normally, an incumbent president faces little formidable opposition within his own party. However, McCarthy, although he was trailing badly in the national polls, decided to pour most of his resources into New Hampshire, the first state to hold a primary election. He was boosted by thousands of young college students, who shaved their beards and cut their hair to be “Clean for Gene”. These students rang doorbells and worked hard in New Hampshire for McCarthy. On March 12, McCarthy won 42% of the primary vote to Johnson’s 49%, an amazingly strong showing for such a challenger, and one which gave McCarthy’s campaign legitimacy and momentum. The momentum ended, however, when Senator Kennedy announced his candidacy four days later, on March 16, as McCarthy supporters cried betrayal and vowed to defeat Kennedy. Thereafter McCarthy and Kennedy would engage in an increasingly bitter series of state primaries; although Kennedy won most of the primaries, he could never shake McCarthy and his devoted following of antiwar activists, which included many Hollywood celebrities such as Paul Newman, Barbra Streisand, and Burt Lancaster.
Johnson withdraws
On March 31, 1968, following the New Hampshire primaries and Kennedy’s entry into the election, the President startled the nation by announcing he would not seek re-election. (Not discussed publicly at the time was Johnson’s concern that he might not survive another term - Johnson’s health was poor, and he had suffered a serious heart attack in 1955. Johnson in fact died two days after the end of Richard Nixon’s first term.) Bleak political forecasts also contributed to Johnson’s withdrawal: internal polling by Johnson’s campaign in Wisconsin, the next state to hold a primary election, showed the President trailing badly, and in fact he lost the primary to McCarthy. With Johnson’s withdrawal, the Democratic Party quickly split into four factions, each of which distrusted the other three.