Election 2016: Campaign run-ins on the July 4th parade route

Sixteen months ahead of the 2016 election, the presidential field is already crowded with 19 candidates. They may come close to literally tripping over each other this holiday weekend, as they vie for attention in a few July 4th parades in a few key early-voting states.

Both the Democratic and Republican candidates are taking the opportunity to show off their patriotism while conducting a little retail politicking -- though according to this 2011 Harvard study, it may help Republicans win over a few more voters than Democrats.

Click through to see where the candidates will be -- and where they may potentially have some awkward run-ins with each other.

Chris Christie, Marco Rubio to march in Wolfeboro, N.H. parade

New Hampshire is a key primary state for any presidential candidate, but particularly for a Northeastern politician with an independent streak like New Jersey Gov. Chris Christie. The governor has hit the Granite State hard since officially launching his bid for the Republican nomination on Tuesday. Over 4 1/2 days, Christie attended several events across the state - town halls, breakfasts, meet-and-greets, roundtables, a smattering of endorsement events - in an attempt to win over New Hampshire voters as John McCain did in 2000 and 2008.

Christie caps off his first official campaign tour of the Granite State in Wolfeboro on Saturday, where he'll attend a GOP breakfast and then march in the Wolfeboro Fourth of July parade on Main Street. Christie could run into Sen. Marco Rubio of Florida, one of his many 2016 GOP opponents, who's also scheduled to march in the parade.

Having two presidential candidates in its Fourth of July parade may seem like a big deal for a town with fewer than 10,000 residents, but Wolfeboro has had its fair share of big-name visitors. In fact, 2012 Republican candidate Mitt Romney has a vacation home in Wolfeboro and has repeatedly marched in the town's Fourth of July parade.

Jeb Bush, Rick Perry, Lindsey Graham in Amherst, N.H. parade

The southern New Hampshire town of Amherst may have just over 11,000 residents, but on Saturday, it'll boast three presidential candidates. Former Florida Gov. Jeb Bush and former Texas Gov. Rick Perry are both walking in the Amherst Fourth of July parade, as is Sen. Lindsey Graham.

Like Wolfeboro, Amherst is accustomed to high-profile politicians paying a visit. In 2014, Sens. Kelly Ayotte and Jeanne Shaheen, as well as Shaheen's GOP opponent Scott Brown, all walked in the Fourth of July parade.

After the Amherst parade on Saturday, Bush and Perry could potentially carpool to the Merrimack parade, in which they're both marching.

Hillary Clinton and Lincoln Chafee traverse the Granite State

New Hampshire is just as critical for Democrats as it is for Republicans, so it's no surprise that Democratic frontrunner Hillary Clinton will make an appearance at the Gorham parade on Saturday. Earlier in the day, Clinton is speaking at a grassroots organizing event in Glen, New Hampshire.

Clinton arrives in the Granite State on Friday, when she'll attend a grassroots organizing event in Hanover followed by a fundraiser in Holderness. The fundraiser will be hosted by Gary Hirshberg, the former CEO of yogurt producer Stonyfield Farm, and his wife Meg.

At least one other Democratic candidate will be traveling across the small state on Independence Day: Former Rhode Island Gov. Lincoln Chafee will be in Merrimack and Amherst.

Bernie Sanders, Martin O'Malley celebrate independence in Iowa

Sen. Bernie Sanders, an independent running for the Democratic nomination, has something of a natural base of support in New Hampshire, since he hails from the neighboring state of Vermont. However, he's also catching up to Hillary Clinton in the early-voting state of Iowa, a new poll shows.

Clinton is still dominating in Iowa with the support of 52 percent of likely Democratic caucus goers, according to a new Quinnipiac poll. Sanders is 19 points behind, but that's an improvement from his standing in May, when he was 45 points behind Clinton in Iowa. Sanders, who's been attracting large crowds on the campaign trail lately, will try to build on his momentum in Iowa this weekend. He's attending a July 4th parade in Creston and another parade in Waukee.

Another Democratic contender, former Maryland Gov. Martin O'Malley, will walk with the O'Malley for Iowa Team and the Buchanan County Democrats in the July 4th parade in the town of Independence. Then O'Malley will attend July 4th barbeques in Dubuque and Clinton.

Flashback to 2007: Candidates meet in Clear Lake, Iowa

If the candidates run into each other on the parade route this year, it won't be the first time. In 2007, for instance, former President Bill Clinton and Democratic candidate Hillary Clinton bumped into Republican candidate Mitt Romney and his wife Ann Romney during the July 4th parade in Clear Lake, Iowa. They engaged in polite chit chat before moving on.

For what it's worth, Clinton came in third in the 2008 Iowa Democratic caucuses, behind candidates Barack Obama and John Edwards. Romney, meanwhile, placed second in the GOP caucuses behind former Arkansas Gov. Mike Huckabee.

Flashback to 1996: Bob Dole is trailed by "Butt Man"

Former Sen. Bob Dole, the 1996 Republican presidential candidate, celebrated the Fourth of July that year in Wheaton, Illinois. Bob Dole celebrated the nation's 220th birthday on the campaign trail in Wheaton, Ill. He walked in the town parade holding a small American flag, in what the New York Times described as "one of the best receptions Mr. Dole has seen in his race for President."

Dole was running to replace then-President Bill Clinton, who spent the holiday in Maryland and Ohio. While Clinton wasn't in Illinois with Dole, the Republican was trailed by "Butt Man" -- a character Democrats brought to life in seven-foot, foam-rubber cigarette costumes. "Butt Man" would follow Dole around, "passing out fake dollar bills that show 'Smokin' Bob Dole' puffing on a scribbled-in cigarette," the New York Times reported -- and he made an appearance on the Democrats' float in the Wheaton parade.