On opposition versus obstructionism

A constructive opposition is one thing, obstructing for the sake of obstructing is another.
And, this is what James Fallows writes about that very issue:

A reader writes:

"I have been waiting for someone somewhere to relate the current Congressional impasse to the 'Turnip Day' special session that Truman called in his acceptance speech at the 1948 Democratic Convention. Some Republicans believed they should complete some unobjectionable legislation in the session, but Leader Robert Taft was adamant that they would yield nothing to 'that son of a bitch the President'. Taft succeeded in making the session an utter failure, but Truman succeeded in demonstrating that the Republicans were obstructionist and he won the campaign meme of the 'Do-Nothing Congress'."This experience of the American electorate punishing rabid partisanship seems too poignant to disappear into history, don't you agree?"

Agree! The official US Senate history of Turnip Day is here; the text of Truman's Democratic Convention speech is here, courtesy of the Miller Center's excellent presidential archives. As the Senate history says about the moment:
"At 1:45 in the morning, speaking only from an outline, Truman quickly electrified the soggy delegates. In announcing the special session, he challenged the Republican majority to live up to the pledges of their own recently concluded convention to pass laws to ensure civil rights, extend Social Security coverage, and establish a national health-care program. "They can do this job in 15 days, if they want to do it." he challenged. That two-week session would begin on "what we in Missouri call 'Turnip Day,'" taken from the old Missouri saying, "On the twenty-fifth of July, sow your turnips, wet or dry."

"Republican senators reacted scornfully. To Michigan's Arthur Vandenberg, it sounded like "a last hysterical gasp of an expiring administration." Yet, Vandenberg and other senior Senate Republicans urged action on a few measures to solidify certain vital voting blocs. "No!" exclaimed Republican Policy Committee chairman Robert Taft of Ohio. "We're not going to give that fellow anything." Charging Truman with abuse of a presidential prerogative, Taft blocked all legislative action during the futile session. By doing this, Taft amplified Truman's case against the "Do-nothing Eightieth Congress" and contributed to his astounding November come-from-behind victory."