Forty-three years after 36 other states approved the concept, the Virginia State Senate today agreed that direct election of U.S. secators was, alas, an idea whose time has come.

But U.S. income taxes?

The Virginia General Assembly, which prides itself on being a slow, cautious body, just is not ready for such a radical idea, said Sen. Joseph T. Fitzpatrick (D-Norfold).

Virginia ratification of the 16th Amendment; which legalized federal income taxes in 1913 was overwhelmingly dilled by a Senate committee last week.

"Why ,they'd have chewed that one up on the floor today," Fitzpatrick said.

As it was, Fitzpatrick, chairman of the state's Democratic Party, said he was thankful he was able to win Senate approval of three of four U.S. constitutional amendments, which most other states long ago approved and have been part of the Constitution for years.

In addition to the 17th Amendment, which provides for the election of U.S. senators, the Senate today approved and sent to the House of Delegates the 15-year-old 23d Amendment, which gives the District of Columbia votes in hte Electoral College and the 13-year-old 24the Amendment, which outlaws the use of the poll tax as a prerequisite for voting.

Although today's Senate vote for the three amendments was 38 to 0, that does not mean that the senators were overjoyed at the prospect of endorsing the amendments, according to Sen. Omer L. Hirst (D-Fairfax), chairman of the committee that earlier had barely approved the measures.

Hirst, the third most senior member of the Senate, said he was astonished to learn that the amendments had never been brought before the Assembly. "I thought they passed a long tome ago," he said.

Members of Hirst's Privileges adn Elections Committee were nonplussed over the measures. They just frumbled, "Why do we have to act on this now?" when Hirst brought up the measures at a meeting last Friday.

Thanks to some quick gaveling by Hirst, Fitzpatrick was able then to win approval of three of the amendments. But there was no agreement to endorse the federal income tax amendment. The voice vote to kill that amendment was "just overwhelming," Fitzpatrick said.

It was not the first time the Virginia legislature has been hesitant to endorse an amendment to the COnstitution. The Assembly did not endorse the women's suffrage amendment until 1952, 32 years after it was ratified by other states. Just this year the Senate, for the first time in four years, agreed to floor debate of the proposed Equal Rights Amendment, but it was defeated here after a prolonged and bitter debate.

Some legislators said that they are reluctant to spend time considering a constitutional amendment that already has won the required approval of three-fourths of the state legislatures in the nation. Many cite the advice Thomas Jefferson once gave to George Washington about legislative matters. "Delay is preferable to error," Jefferson counseled. Both once were members of the Virginia Assembly.

"You may have detected that every now and then some antifederalism seems to emerge from the General Assembly," said Hirst, a courtly Northern Virginian, who, like many legislators here, is prone ot understatement.

Fitzpatrick and others wre surprised today when the consittutional amendments did not encounter opposition on the Senate floor. Consideration of the amendments had been attacked by a Richmond newspaper as a waste of the legislature's time. Such measures also frequently have encountered opposition from conservative senators, many of whom cherish Virginia's political independence and argue that just because other states may have enacted such laws is no reason for Virginia to accept their leadership.

According to Fitzpatrick, Virginia is the first state to act ofn th direct election of senators since 1914, when the Louisiana legislature approved the measure initially drafted by Wisconsin's progressive Sen. Robert M. La Folloette. Fitzpatrick said he did not know why VIrginia had never acted on the amendment and said his interest was generated by his 16-year-old daughter, Regis, who was studying the COnstitution in a high school class and had asked him why the state had not acted.

Fitzpatrick said he had no idea how the 100-member House of Delegates will react to the amendments. "It just depends on their mood that day," he said.