(CNN) -- In her first solo appearance on the campaign trail, Alaska Gov. Sarah Palin told voters Monday they need to send her and John McCain to the White House so they can "shake things up."
"In the next 50 days, Colorado, it's going to be a hard-fought contest here," Palin said in Golden, Colorado, one of the state's swing districts. "We're taking our case for reform to voters of every background, in every party or no party at all. And with your vote, we're going to Washington to shake things up."
She told voters that should she become vice president, she would focus on energy security, government reform and helping families that have children with special needs.
Democratic presidential nominee Barack Obama was also in Colorado on Monday, holding an event in Grand Junction.
Colorado is a key swing state, with nine electoral votes at stake.
At his Colorado event, Obama attacked McCain's call for change and said the Republican candidate was using his lines.
"He has argued that what qualifies him to be president is the quarter-century he spent in Washington," Obama said. "But now suddenly, John McCain says he's about change. He's even started using some of my lines."
"Let me tell you something. Instead of borrowing my lines, he needs to borrow some of our ideas," he added.
McCain on Monday blamed Obama for the increasingly brutal tone on the trail. Watch McCain address Florida voters »
"Sen. Obama's been saying some pretty nasty things about Gov. Palin and me," he said. "...That's OK. He can attack if he wants, but all the insults in the world aren't going to bring change to Washington," he said in Jacksonville, Florida.
Obama's running mate, Sen. Joe Biden, also hammered McCain's message of change at an event in St. Clair Shores, Michigan.
Biden, one of McCain's decades-long Senate colleagues, accused the Arizona senator of being a "sequel" to President Bush's two terms.
"We've seen this movie before," Biden said. "And we know, the sequel is always worse than the original." Watch Biden slam McCain »
"If you're ready for four more years of George Bush, then John McCain is your guy," he said, adding that "McCain could easily become known as 'Bush 44,' " a reference to Bush being the 43rd U.S. president.
The speech marked Biden's second visit to Michigan since being selected as Obama's running mate.
The speech on domestic issues is one of two framing speeches Biden will deliver before the fall debates. The second will be on foreign policy next week.
Biden, a senator from Delaware, also argued that McCain is "profoundly out of touch" with the issues that average Americans face.
"When someone running for election changes his views to satisfy the base of the party, that's not change, that's just more of the same Washington game," Biden said.
Biden also addressed the negative tone the race has taken in recent days, arguing that it is because the staff that McCain has hired is the same team Bush used against McCain to launch "unconscionable, scurrilous attacks" in the 2000 race.
"The campaign a person runs tells you everything about the way they'll govern," Biden said. "The McCain-Palin campaign decided to bet the house on the politics perfected by [former Bush adviser] Karl Rove."
Biden said he considers McCain his close friend and someone who has served the country bravely, but added, "America needs more than a brave soldier. They need a wise leader."
Obama's campaign released a new ad Monday that accuses McCain of "deception."
"What happened to John McCain?" asks the announcer in the 30-second spot, "Honor."
The ad quotes commentators calling the Arizona senator's ads "vile" and filled with "dishonest smears" from a "disgraceful, dishonorable campaign."
"After voting with Bush 90 percent of the time, proposing the same disastrous economic policies ... it seems 'deception' is all he's got left," says the announcer.
The McCain campaign quickly responded. "As Americans face economic uncertainty, it is clear that Barack Obama would sooner hurl insults than discuss his record of seeking higher taxes during a down economy, opposing additional off-shore drilling to reduce energy prices and voting the partisan line nearly 100 percent of the time," said McCain spokesman Tucker Bounds.
"This latest ad by Barack Obama is a desperate effort to move away from talking about his thin, but alarming record on the issues, and it isn't going to reform Washington or strengthen our economy."
CNN's Alexander Marquardt and Rebecca Sinderbrand contributed to this report.