Arizona Sen. John McCain is expected to formalize his campaign for the 2008 Republican presidential nomination early in February, holding off on a formal announcement while he gets his nationwide campaign ready to roll.

McCain will have final conversations with his family over the holidays, sources told FOX News on Monday, and in early January will all but announce an official campaign. The sources said the start of the new Congress is guiding McCain's schedule, and he will hold off until February to make visits to crucial primary states like Iowa, New Hampshire and South Carolina.

The Arizona Republican is aiming to create a campaign organization that will rival, and possibly surpass, that of George W. Bush's 2000 and 2004 campaigns. McCain ran against Bush in the 2000 election, winning the New Hampshire primary but eventually losing the nomination. Now, he is turning to President Bush's winning template, drawing on Bush's Pioneer and Ranger fundraisers, the powerhouse groups of donors who helped raise record amounts of cash.

McCain's 2007 fundraising goals are said to be $25 million by June and $50 million by November, and the campaign will likely be staged from Washington. D.C., with offices in Arizona as well as key primary states.

McCain, who spent the weekend in Afghanistan and is returning late Tuesday from touring the Middle East with a group of senators, called on European countries to devote more resources to Afghanistan to prevent destabilizing influences like drug trade and extremists. McCain also has been calling for an increase of troop levels in Iraq of up to 30,000 additional troops, running counter to most Democrats as well as the findings of the Iraq Study Group, which released 79 recommendations earlier this month.

McCain has said the additional troops would help to stabilize the country. The Bush administration suggested last week the president could propose such a plan next month.

Even before he has tossed his hat into the ring of official presidential contenders, McCain faced criticism from one potential Democratic rival, Iowa Gov. Tom Vilsack, who is seeking the Democratic nomination in 2008.

Vilsack sent a letter to McCain on Monday, calling McCain's plan for troops in Iraq "a big mistake."

"Your suggestion to deploy additional American servicemen and women to Iraq would make a big mistake even bigger and send the wrong message to President Bush, who has stubbornly refused to recognize that his administration's military and diplomatic failures in Iraq have recklessly endangered America's national interests," Vilsack wrote.

FOX News' Carl Cameron contributed to this report.