Has President Obama been listening to a lot of Jimi Hendrix lately? With just under two months to go before Election Day, Obama kicked off the fall campaign season Monday with an aggressive speech targeting Republicans. But it was an off-script moment in the speech that's attracted the most attention, as Obama accused his GOP critics of talking about him "like a dog." "Some powerful interests who had been dominating the agenda in Washington for a very long time -- and they're not always happy with me -- they talk about me like a dog. That's not in my prepared remarks, but it's true," Obama said during a speech at Wisconsin's Laborfest on Monday. Though Obama didn't acknowledge it, the line was a verbatim quote from "Stone Free," the first song Hendrix wrote after moving to England in 1966. "They talk about me like a dog," the song says. "Talkin about the clothes I wear. But they don't realize they're the ones who's square." It's unclear if Obama consciously or unconsciously cited the lyric. A White House spokesman did not respond to requests for comment. But regardless of its source, Obama's off-script message syncs with his overall frustration with Republicans, whom he has lambasted repeatedly as the "party of no." With polls showing Democrats still trailing badly as the midterm campaign enters its post-Labor Day upsurge, Obama stepped up that attack line Monday. In his remarks, he suggested that the GOP will always block bipartisanship, no matter the situation. "If I said the sky was blue, they'd say no," he vented. "If I said fish live in the sea, they'd say no. They just think it's better to score political points before an election than to solve problems." It's all a part of the Democrats' efforts to convince Americans that a vote for the GOP this fall would return the country back to the state it was in before Obama won the presidency. Though polls show the effort isn't working, Obama has made the argument again and again, tying it to the issue that seems to be driving voters this fall: the economy. "They're betting that between now and November, you'll come down with a case of amnesia. They think you'll forget what their agenda did to this country," Obama said. "They think you'll just believe that they've changed. These are the folks whose policies helped devastate our middle class and drive our economy into a ditch. And now they're asking you for the keys back."