Democratic nominee Michael Dukakis said Monday the campaign against George Bush will be "a long, hard competitive race," while aides to Bush said the vice president will continue to paint his rival as weak on defense.

Dukakis' running mate, Texas Sen. Lloyd Bentsen, continued to cast doubts on Republican vice presidential candidate Dan Quayle's experience."Frankly, he would not have been on my short list as I look over my Senate colleagues," Bentsen said Sunday on NBC's "Meet the Press." "He obviously was on the short list of the hard right.

"Now, I wouldn't say that he couldn't grow into the job; he probably could. But if a tragedy befell a president, you'd have to be able to move in immediately and take over and do what has to be done in facing whatever issues that confront you at that time."

Dukakis kicked off a two-day visit to the western section of his home state, Massachusetts, where he sought to halt the recent surge of his Republican opponent.

"It's going to be a long, hard competitive race," Dukakis told the Northern Berkshire Chamber of Commerce. "One thing that inspires me every day and every week out there on the campaign trail is that I know we can do it together because I've seen it happen."

Bush's chief of staff, Craig Fuller, said the vice president will continue to stress his pro-military views and portray Dukakis as weak on defense. The GOP nominee's campaign believes that theme is going over well.

Bush was traveling Monday from Houston to St. Louis, where he planned a tour of an aerospace plant, and then to Nashville for a rally and visit to the Reserve Officer Training program at Middle Tennessee State University.

He returns to Washington late Monday and plans a series of day campaign trips before heading to California and Colorado on the weekend.

Bentsen, in suggesting that Quayle could not step right up to presidency, was continuing a line of attack that was clear last week: show that the 41-year-old Indiana senator lacked the depth and experience for the job that is only a heartbeat away for any vice president.

Quayle declined to criticize his 67-year-old colleague, saying that his gripe is with Dukakis. In last week's seven-state campaign, Quayle's only mention of Bentsen was to praise his views on defense spending and other issues where he stands to the right of Dukakis.

"I've served with Sen. Bentsen for almost eight years. He is not the issue," Quayle said Sunday in an interview with The Associated Press. "The issue is Michael Dukakis. Michael Dukakis' view of America is a much different view than George Bush's. Michael Dukakis' approach to national defense, his approach to the economy, his approach to child care - all of those approaches are much different than George Bush's."

Quayle said doubts about his qualifications are nothing that a good debate wouldn't cure.

Former presidential candidate Jesse Jackson, interviewed on ABC's "This Week with David Brinkley," said that the Dukakis campaign can become too preoccupied with trying win back conservative Democrats who have been voting for Ronald Reagan.

He said that more could be accomplished by massive registration of new voters, and reaching out to the working and non-working poor.