WASHINGTON, D.C. - The contests for the Republican and Democratic U.S. presidential nominations are far from over, with not quite half of the 50 states having picked delegates to the parties' national nominating conventions in July.
Key primary election and caucus contests are scheduled in the coming weeks, with March 15 a key date on the campaign calendar.
Here's where both parties stand at the moment, after Saturday's voting in five states.
Democratic Nomination Contest
A total of 2,382 delegates is needed to secure the party's nomination.
Former Secretary of State Hillary Clinton has collected nearly half that total, leading her lone opponent, Vermont Senator Bernie Sanders, by a 1,121-to-481 margin.
She has built much of her lead by accumulating pledges of support from so-called "super delegates," who are party and elected officials who favor her candidacy no matter the outcome of voting in their states.
Sanders defeated Clinton in two Midwest states Saturday, Kansas and Nebraska, but Clinton won in a bigger state, Louisiana, in the southern United States and gained a few more delegates than Sanders did.
Clinton, the country's top diplomat from 2009 to 2013, has now defeated Sanders, a democratic socialist, in 11 of the 18 states that have voted.
Republican Nomination Contest
Billionaire real estate mogul Donald Trump, a political novice, continues to lead the Republican field, which has been winnowed from 17 original candidates.
Trump is still being opposed by two senators of Cuban-heritage, Ted Cruz of Texas and Marco Rubio of Florida, and the governor of a Midwestern state, John Kasich of Ohio.
In the Republican contest, the winner needs 1,237 delegates. So far, Trump has 378, Cruz 295, Rubio 123 and Kasich 34.
Trump has won victories in 12 states, Cruz six and Rubio one.
On Saturday, Cruz closed the delegate gap with Trump, routing him in Kansas and Maine, and losing narrow contests in Kentucky and Louisiana.
Both parties are holding several primaries and caucuses during the coming days, with a key vote Tuesday in the large Midwestern state of Michigan.
An NBC News/Wall Street Journal poll released Sunday showed Clinton and Trump with commanding leads in the state.
The survey, conducted in recent days, showed Clinton ahead of Sanders, 57 to 40 percent. In the Republican race, Trump leads with 41 percent of likely primary voters, followed by Cruz at 22 percent, Rubio at 17 percent and Kasich with 13 percent.
On March 15, a week after the Michigan contest, there are primaries in two other big states that often prove to be crucial in national elections, Ohio in the Midwest and Florida in the southeastern part of the country.
The two states are particularly important in the 2016 Republican campaign for the party's presidential nomination.
In the contests leading up to March 15, convention delegates are being apportioned by the vote counts in each state, but both the Florida and Ohio votes are winner-take-all primary elections.
Rubio said he expects to win his home state, and Kasich said the same for the state he governs.
The winners of the two parties' nomination contests will face each other in the national election on November 8 to pick the successor to President Barack Obama, who leaves office in January 2017 after eight years in the White House.
The U.S. Constitution limits presidents to two four-year terms.