SACRAMENTO - Frustrated that presidential candidates have spent so little time in California, lawmakers approved legislation yesterday to change how the state awards its electoral votes for president.

The bill, approved 49-31 mostly along party lines in the Assembly, would pledge California's 55 Electoral College votes to the winner of the national popular vote, a system critics charged was an attempt to circumvent the U.S. Constitution.

If the bill became law in California, it would take effect only if states with a combined total of 270 electoral votes - the number required to win the presidency - also agreed to decide the election by popular vote.

The interstate compact the Assembly authorized is part of a national campaign launched in February by a Los Altos nonprofit to change the way the nation picks a president.

"Presidential candidates would have to come to California because of our population, and they would have to take a position on issues that we care about," Assemblyman Tom Umberg, D-Santa Ana, said on the Assembly floor.

The Constitution requires each state to select its Electoral College delegates in presidential races. California awards its votes based on the state popular vote, as do most other states.

Backers of the compact say presidential candidates should be forced to campaign before all voters, not just those in so-called battleground states such as Ohio, Michigan, Pennsylvania and Florida....

A compact agreement would require California to give its electoral votes to the winner of the national vote regardless of which presidential candidate state voters select.

Critics said a popular vote system would send presidential candidates only to the most populous cities, shutting out rural America....

The Colorado Senate in April voted to ratify the compact. The proposal also is being considered in four other states - New York, Louisiana, Illinois and Missouri.