Why did some democrats oppose hubert humphrey in his 1968 race for the presidency?

they did not agree with his stand on civil rights.
they refused to back a republican candidate for president.
they did not like his association with the administration’s vietnam policy.
they wanted president johnson to run for a second full term.

They did not like his association with the administration’s Vietnam policy. is why did some Democrats oppose Hubert Humphrey in his 1968 race for the presidency. Option three is correct.

Hubert Horatio Humphrey Jr. was an American politician who served as the 38th vice president of the United States from 1965 to 1969. He worked twice in the United States Senate, representing Minnesota from 1949 to 1964 and 1971 to 1978. He was the Democratic Party's nominee in the 1968 presidential election, claiming defeat to Republican nominee Richard Nixon.

a.tensions between the colonial elites and the backcountry men of virginia.

porter is writing economic history because he is focusing on the cost of developing vaccines.