DES MOINES, Iowa (AP) — Both Democratic presidential candidates were forced onto the defensive: Vice President Al Gore mending fences with Gen. Colin Powell and backpedaling on a sticky question of gays in the military, Bill Bradley buying TV time to justify the very premise of his "big ideas" campaign.

The sparks were flying even before the pair went head to head in today's debate.

Feeling the pinch of Gore's latest line of criticism — likening the Bradley agenda, top-heavy with a massive health care plan, to Ronald Reagan's for its focus on only "one or two things" — the Bradley campaign said it spent $250,000 on a new television ad that would pelt New Hampshire voters five or six times on Manchester TV and another five or six times from nearby Boston stations.

"People accuse me of offering big ideas that they say are risky," Bradley says in the ad. "I say the real risk is not doing the things I've set out to do in this campaign."

It marked the first time that Bradley, in his active ad campaign, used a spot to respond to Gore. It also marked a sharp escalation in the back-and-forth of the tight race for Iowa's Jan. 24 delegate caucuses and New Hampshire's Feb. 1 primary.

Over in the Gore camp, the back-and-forth was internal as Gore, within the space of one hour Friday evening, juggled two self-deployed political land mines.

He tried to clear up an embarrassment caused by his campaign manager and then, hastily called a news conference — safely after most dinnertime news broadcasts — to retract comments earlier in the week that he would require candidates for the Joint Chiefs of Staff to agree with his intention to let gays serve openly in the military.

"I did not mean to imply that there should ever be any kind of inquiry into the personal political opinions of officers in the U.S. military," Gore said after a pep rally at Valley High School.

Gore, under fire from military brass and some of his own political allies, spoke two days after his original comments during a debate in New Hampshire. The comments sparked dissent from former members of the joint chiefs and from Sen. John Kerry, a decorated Vietnam veteran campaigning for Gore.

In what aides called a "clarification" of his original statement, Gore said, "What I meant to convey was I would not tolerate, nor would any commander in chief, nor would any president tolerate orders not being followed."

The line seemed to be borrowed from Bradley. Both Democrats were asked in Wednesday's debate if they would make agreement on gays in the military a litmus test for appointments to the joint chiefs.

Bradley said such a test was unnecessary because military officers follow orders from their commander in chief, no matter what.

But Gore answered the litmus-test question this way: "I would insist, before appointing anybody to the Joint Chiefs of Staff, that that individual support my policy. And yes, I would make that a requirement."

After two days of news reports quoting current and retired military officers aghast at Gore's remark, the vice president blamed reporters for not hearing him right.

"That is not what I meant to convey — that's what you heard," he said. "I didn't use that term, litmus test."

At Gore's campaign rally, supporter Carolyn Klein faulted Gore for ever suggesting such a prerequisite. "What matters is if he can work well with them, and not whether they agree or disagree. Not everyone agrees with me on my job either but we work together," said Klein, a food-service director for the local school district.

But Klein, 59, also faulted Gore for wasting energy on the question. "I think that's the least of our issues right now. We have so many problems to work on, that he's making too much of that."

As for the day's other thorny distraction, Gore campaign manager Donna Brazile said in a recent interview that Republicans used blacks like General Colin Powell, former chairman of the Joint Chiefs of Staff, to pose for pictures, but did not really care about them.

Powell responded with an angry letter to the Gore campaign that he distributed to reporters.

Brazile and Gore separately telephoned Powell. Gore refused to say whether either of them apologized outright to the retired general.

"We're friends of long standing ... it was a very friendly and warm conversation," Gore told reporters. "I reaffirmed my total respect and regard for him as an American hero, for him as a national leader and for him as a personal friend."

Republican presidential candidates normally preoccupied with their own nomination pounced on Gore for the missteps.

Front-runner George W. Bush called the Powell remark by Brazile, who included Oklahoma GOP Rep. J.C. Watts in her indictment, "slash-and-burn politics" and said he would "watch and see how Gore handles it."