If you think this has been a strange campaign for president, you’re right — and not just because of the accusations of sexual harassment aimed at Herman Cain in recent days or cable chatter about Texas Gov. Rick Perry’s caffeinated speech in New Hampshire a week ago. In five big ways that have nothing to do with those developments, the Republican race is breaking with patterns of the past.

The first goes back to the beginning. This is one of the latest-starting, slowest-developing and most changeable nomination battles in modern memory.

In the previous campaign, John McCain filed his papers with the Federal Election Commission days after the 2006 midterms. At least two Democrats held formal announcements before the end of the year. Mitt Romney was in shortly after New Year’s Day 2007. Barack Obama and Hillary Rodham Clinton were up and running in January 2007 and never slowed a step.

This time around, the candidates strolled rather than sprang to the starting gate. So eager were the media to get the race moving that every baby step by anyone toward a formal candidacy was covered as if it were news.

Romney didn’t file his papers until spring. Newt Gingrich had made several false starts toward filing by then but did not finally become a candidate until later in the spring. Herman Cain formally joined in May, Michele Bachmann and Jon Huntsman in June. Perry didn’t announce until August.

That hesitancy fed the second difference between campaign 2012 and others. This year’s contest has also been notable for the number of prominent Republicans who talked about running, and in some cases were urged to run, but who ultimately chose not to. They include former Arkansas governor Mike Huckabee, businessman Donald Trump, Indiana Gov. Mitch Daniels, Mississippi Gov. Haley Barbour, former Florida governor Jeb Bush, former Alaska governor Sarah Palin and New Jersey Gov. Chris Christie.

You could go back to 1992 and the Democrats for a similar pattern. That year, Al Gore, Bill Bradley, Dick Gephardt and Mario Cuomo all chose not to run. What’s different is that, in that case, George H.W. Bush was seen as virtually unbeatable because of the Persian Gulf War (how wrong those assumptions were). This year, with President Obama on the defensive, the Republican nomination is well worth having, and yet an all-star roster of GOP leaders took a pass.

It isn’t just that some big names didn’t run. It is the attention they got at the time. Their public considerations soaked up a significant amount of coverage and commentary. A speech by Cheri Daniels, who didn’t want her husband to run, drew national coverage. The attention paid to the non-candidates overshadowed and diminished those who were in the race.

That illustrates the third big difference. In this nomination battle, there really hasn’t been a dominant front-runner, as there has been in the past. Romney is generally described as the front-runner and has been from the start. But some months ago, the Gallup organization described him as one of the weakest front-runners in the modern history of Republican races, given that he has been stuck or stable in the polls at about 25 percent.

More telling, perhaps, is the fact that seven people have had a share of the lead in the Republican race at some point this year in one or more polls. Seven! They are: Romney; Huckabee; Trump; Palin; former New York mayor Rudy Giuliani; Perry; and Cain. Has there ever been a more fluid race or a more unpredictable GOP electorate?

The fourth big difference is in the way candidates are running their campaigns, based on traditional measurements of activity. Start with fundraising. At the end of the third quarter in 2007, Republican candidates collectively had raised about $230 million. This year, the field has raised just $85 million. Everyone says fundraising is more difficult this year. There is the proof.

Four years ago, Romney alone had raised $85 million by the end of the third quarter, including a chunk of cash from his own fortune. His total through the third quarter of this year is $44 million, even though he is considered the front-runner and has spent considerable time since his campaign began tending to his finance network. The one candidate not feeling the pinch is Ron Paul. He has raised $12.6 million this cycle compared with $9 million through September 2007.

Candidates are also spending less time in the early states. Last week, a team at National Journal’s Hotline compared the number of days spent in Iowa and New Hampshire this year compared with the last campaign.

Four years ago, between July 1 and Nov. 1, Huckabee, Romney and McCain spent a combined 48 days in New Hampshire and 66 days in Iowa. This year, Romney, Perry and Cain collectively have spent 37 days in New Hampshire and 23 days in Iowa. Cain has spent just six days in New Hampshire and 11 days in Iowa since July 1.

To be fair, some candidates are spending oodles of time in some of the early states. Rick Santorum has been all over Iowa. Huntsman is hunkered down in New Hampshire. But neither state has yet to become the scene of a truly engaged battle (with the exception of the brief but intense competition in Iowa last summer between Bachmann and former Minnesota governor Tim Pawlenty).

Republicans don’t always organize the early states with the depth and intensity of the Democrats, but this is another area where the thinness of state operations is telling. Four years ago, Obama had more than 30 offices in Iowa. John Edwards, who finished second in the caucuses, had 20 or more by this time, with more than 100 paid staffers, and had county chairs in all 99 counties and precinct leaders in roughly 80 percent of the 1,800 precincts.

By comparison, Romney has one office, in Des Moines, with four paid staffers, according to one of his advisers. Perry has five offices. His Des Moines headquarters has four paid staffers. He has one each in four other cities. Cain has one office and four paid staffers. As of a couple weeks ago, no one had announced county chairs in all 99 counties, according to one Iowa strategist. One caveat: Officials with the current campaigns note that Huckabee had only one office four years ago and still won the caucuses.

Lack of money means lack of advertising. By Nov. 1, 2007, Republicans had spent $11.3 million on ads, according to Kantar Media’s Campaign Media Analysis Group. Romney spent almost all of that, buying ads in New Hampshire, Iowa, South Carolina, Florida, Maine, Massachusetts, Michigan and Georgia.

So far this year, all the GOP candidates combined have spent $1 million — more than two-thirds of it by Ron Paul. Less than $300,000 has been spent in New Hampshire. As of last week, Romney hadn’t spent a dime anywhere, according to the CMAG.

That brings us to the fifth and most important difference. Republicans are engaged in a national campaign, one that has played out less in living rooms in Iowa or town halls in New Hampshire and more on debate stages in those and other states, on prime time and Sunday morning shows on Fox News and through cable commentary, blog posts and tweets. Debates have shaped and reshaped the field and are likely to produce more changes before the New Year arrives and the primaries and caucuses begin. GOP candidates can get their message out to activists by appearing on Fox as often as they’re welcome. (Note that Romney has been the least visible here.) Social media may be playing more of a role than anyone knows in organizing efforts, but no one can tell that yet.

Whether all this is an aberration or the new normal, no one knows. Come January, states that may be feeling neglected right now will come roaring back into prominence, starting in Iowa on Jan. 3, New Hampshire a week later and then South Carolina, Florida and Nevada over the subsequent four weeks. The campaign will return to some semblance of regular order. But so far we’ve been witnessing something new.