Washington ? Thrown off stride by a hard-charging campaign from Republican rivals John McCain and Sarah Palin, Barack Obama moved Friday to reclaim the spotlight and assure worried supporters that he can and will fight back.

“We will respond with speed and ferocity to John McCain’s attacks and we will take the fight to him,” Obama campaign manager David Plouffe said in a memo Friday.

“But we will do it on the big issues that matter to the American people. We will not allow John McCain and his band of Karl Rove disciples to make this big election about small things.”

Obama immediately launched a new ad that notably omitted any mention of Palin – an abrupt switch after days of criticizing her.

It was an apparent recognition that the Democrats have helped raised the Alaska governor’s profile by criticizing her for days, a move that may have helped the Republicans. Palin has drawn huge crowds, energized the Republican base and helped Republicans draw the kind of volunteers they needed, but lacked, to turn out votes in battleground states.

The new Obama ad hit McCain hard, ridiculing him as a computer illiterate who doesn’t know how to use e-mail and working to cast the 72-year-old Arizonan as out of touch with ordinary Americans.

At the same time, Obama supporters tried to seize on a comment McCain made the night before at a forum on service in which he defended Palin’s experience as a small-town mayor by saying she was closer to real people than he was in the Senate.

“It’s easy for me to go to Washington and frankly be somewhat divorced from the day-to-day challenges people have,” McCain said at the Thursday forum in New York.

Obama pounced on Friday in New Hampshire, saying, “From where he and George Bush sit, maybe they just can’t see. Maybe they are just that out of touch. But you know the truth, and so do I.”

Obama hoped the steps would calm donors and a base that’s been agitating for more fight from him as some Democrats wring their hands over the Republican ticket’s post-convention bump in polls.