Correction: An earlier version of this story incorrectly stated that 16 Democrats have been president. Sixteen presidents have been Democrats; Grover Cleveland counts twice because he was both the 22nd and 24th president. This story has been updated.

(The Washington Post)

You may already know that 2016 is a presidential election year. Under the Constitution, Barack Obama cannot seek a third term, so in November, voters will elect a new president, who will be sworn in next January.

The field of would-be presidents is big. The two major political parties, Republicans and Democrats, will choose their party’s nominee through a series of events called state primaries and caucuses. That process begins Monday in Iowa.

The two parties hold their national conventions in July. That’s when their choices for president and vice president (known as the party’s “ticket”) will be formally approved.

In addition to the Republican and Democratic candidates (pictured on this page), there are several independent and third-party hopefuls in the race. It promises to be a mad dash to the finish line on Election Day.

Who can run for president?

The Constitution lists three requirements: You must be at least 35 years old, have been a U.S. resident for at least 14 years and be a “natural-born citizen” of the United States.

That last requirement is tricky. The Founding Fathers did not spell out what “natural-born” means. One of the 2016 Republican contenders is Ted Cruz, a U.S. senator from Texas. He was born in Canada to an American mother and a Cuban father. His mother’s American citizenship automatically made Cruz a U.S. citizen. But is he a “natural-born” citizen? A court might be asked to decide.

The two major political parties choose their candidates for president and vice president at national conventions. Balloons cascade the crowd at the 2012 Republican Convention, which was held in Tampa, Florida. (Brendan Smialowski/Agence France-Press via Getty Images)
Political parties

People who share political views join together to win elections and advance their goals. The two major U.S. parties are the Republicans (also known as the GOP, or “grand old party”) and the Democrats.

The Democrats trace their history to the 1790s and Thomas Jefferson. The Republican Party formed in the 1850s, before the Civil War. Abraham Lincoln was the first Republican president, elected in 1860.

In all, 18 presidents have been Republicans and 16 have been Democrats. (Grover Cleveland, a Democrat, counts twice; he was the 22nd and 24th president.) The last one from a different party was Millard Fillmore in the early 1850s. He was a Whig.

Johnnie P. Patton, a delegate to the 2012 Democratic National Convention in Charlotte, North Carolina, wears a hat showing her support for President Obama. (Bonnie Jo Mount/The Washington Post)
Where they stand

At their nominating conventions in July, each party will approve a “platform” of its positions on many issues. Their candidates will usually support those positions, but they aren’t required to.

In general, Republicans favor a smaller federal government, with more power given to the states. They favor widespread tax cuts as a way to boost the economy. Democrats believe in a bigger federal government that makes rules for business and that spends more money on social services such as health care. They back some tax cuts but not for the wealthy or corporations.

The issues

Education, climate change, the environment and foreign policy are among the important issues the candidates face. Here are a few more:

●Immigration: Should people who entered this country illegally be allowed to stay?

●Gun control: Should there be stricter rules about guns and who can buy them?

●Health care: What role should the government play in providing this and other social services?

●Terrorism and national security: How should the government protect America and its allies, or friendly foreign countries?

●The economy: What should be done to boost the recovery from the 2008-2009 financial crisis?

Did you know . . . ?
Donkeys and elephants

The Republican symbol is an elephant. The Democrats’ is a donkey. The donkey dates to the election of 1828, when opponents of Andrew Jackson labeled him a “jackass.” He thought it was funny and featured the image in campaign posters. In 1870, political cartoonist Thomas Nast used the donkey to refer to the Democratic Party. A few years later, Nast drew a cartoon that included an elephant with the words “the Republican vote” on its side. Soon after, the animals became widely associated with the two political parties.

On election night in 2004, workers walk on a giant presidential election map in the skating rink at Rockefeller Center in New York City. The states in red went for President George W. Bush and the blue states for Senator John Kerry. The white states were undecided at the time. (Kathy Willens/AP)
Red versus blue

More recently, the colors red and blue have been used to distinguish one party from another. The practice began in 2000, when the TV networks colored their maps to indicate which party was winning where. States that voted for the Republican presidential candidate were shown in red; those that voted for the Democrat were blue.

Family ties

Two of the 2016 candidates are hoping to keep the White House in the family. Democrat Hillary Clinton, a former secretary of state and U.S. senator, is married to former president Bill Clinton. And Republican Jeb Bush, a former governor of Florida, is the son and brother of two former U.S. presidents, George H.W. Bush and George W. Bush.

On the other hand . . .

Three of the Republican candidates have never been elected to a state or national office. They are businessman Donald Trump, retired neurosurgeon Ben Carson and former business executive Carly Fiorina.

What’s the tab?

Democracy doesn’t come cheap. Estimates of the cost of the 2016 election start at $3 billion. It will be spent on campaign ads, air travel, hotel stays, staff salaries and other expenses.

A trip to the polls, or voting locations, can get you a sticker — and a sense of pride. (Seth Perlman/AP)
Get out and vote

You must be at least 18 years old to vote in a presidential election. In 2012, fewer than 6 in 10 eligible voters cast ballots, a slight drop from 2008. Minnesota led all states, with more than 75 percent of eligible voters going to the polls. Hawaii was last, at 44 percent.

Click to read timeline. (The Washington Post)
Let us hear from you

KidsPost will be checking in on the campaign between now and Election Day in November. Tell us what you would like to read about. More about the candidates? Is there an issue you want us to explore? Are you interested in presidential history? Presidential pets? Kids who lived in the White House?

Send your suggestions and questions to or KidsPost, The Washington Post, 1301 K Street NW, Washington, D.C. 20071.