WASHINGTON – Major League Baseball should enforce stronger rules against steroid abuse by players on its own, but Congress will require changes by law if necessary, leading lawmakers said yesterday.

Senator McCain, the driving force behind changing how baseball polices performance-enhancing drug use, said yesterday he believes President Bush would sign a bill into law.

“There’s not a doubt in my mind. He’d love to,” said Mr. McCain, who accompanied Mr. Bush to Saturday’s Army-Navy college football game in Philadelphia.

He added that Mr. Bush, too, would prefer for baseball to act on its own. “I know that the president would like to see it done through collective bargaining and decision made by owners and labor,” said Mr. McCain, a Republican of Arizona. Other lawmakers, including the top Republican in the Senate and the House’s top Democrat, expressed similar sentiments as cries grew louder for baseball to act.

The executive board of the players’ union starts its annual meeting today in Phoenix with the issue on its agenda

Lawyers for baseball Commissioner Bud Selig’s office and the union have met several times to discuss Mr. Selig’s repeated calls for more frequent testing and harsher penalties for steroid use. The current once-a-year testing policy expires in 2006.

The matter has become urgent since the San Francisco Chronicle reported last week details of players’ testimony to a federal grand jury that indicted four people on charges of illegally distributing steroids to top athletes.

One of those indicted was the personal trainer of the San Francisco Giants’ Barry Bonds, whose 73 home runs in 2001 is the game’s single-season record and who is 53 homers away from breaking Hank Aaron’s all-time record of 755. Mr. Bonds told the grand jury he used a cream and a clear substance but didn’t know they were forbidden.

“The important aspect of this issue is that high school kids all over America believe that this is the only way they can make it,” Mr. McCain said on “Fox News Sunday.”