A year out from Election Day, the field of presidential candidates is slowly shrinking. But with 17 people running for the Democratic nomination, it’s still historically large.

While in part a measure of the desire to oust President Donald Trump, the large field has also made it harder for the top contenders to forge a more focused contest. Former Vice President Joe Biden has led most national polls since he joined the race, but he’s slipped some as other candidates, most notably Sen. Elizabeth Warren, have risen. Trump has picked up a few long-shot Republican challengers, too.

Michael Bennet, senator from Colorado

Bennet, 54, a moderate known for seeking compromise, has called for modernizing the economy in fields like artificial intelligence and for increasing infrastructure spending. In early April, he announced that he had prostate cancer, but he has since had surgery that his staff called “completely successful.”

Joe Biden, former vice president

Biden, 76, is known for his down-to-earth personality and his ability to connect with working-class voters. He has run for president twice and considers 2020 his last shot at the White House. He wants to restore America’s standing on the global stage and strengthen economic protections for low-income workers.

Cory Booker, senator from New Jersey

Booker, 50, one of the most gifted orators in the field, is running on a politics of uplift that recalls President Barack Obama’s 2008 campaign. Booker has been one of the leaders in the Senate on criminal justice reform and has proposed a government-run savings program called “baby bonds” to curb inequality.

Amy Klobuchar, senator from Minnesota

Klobuchar, 59, has called for Democrats to focus on reclaiming the swing states in the middle of the country, pitching herself as a pragmatist who can win there. She has championed legislation to combat the opioid crisis and drug addiction, and to address the cost of prescription drugs.

Wayne Messam, Miramar, Fla., mayor

Messam, 45, of Florida, has taken progressive stances on guns, immigration and environmental issues. A first-generation American born to Jamaican parents, Messam is hoping to tap into the Caribbean-American community to help fuel his long-shot bid. But he reported raising just $5 in the third quarter of 2019.

Bernie Sanders, senator from Vermont

Sanders, 78, a self-described democratic socialist, has brought progressive proposals like Medicare for All and tuition-free public college to the forefront of the race. He has faced questions about his age and health, particularly after he had a heart attack last month. “I feel great,” he said as he left the hospital.

Joe Sestak, former member of Congress from Pennsylvania

Sestak, 67, a former Navy admiral, was the highest-ranking military officer ever elected to Congress in 2006. He scored a long-shot win in the 2010 Democratic primary in Pennsylvania for U.S. Senate but lost the race. He wants to work on combating climate change and restoring America’s place in the world.

Tom Steyer, billionaire activist

Steyer, 62, casts himself as a progressive outsider, calling for term limits in Congress, decriminalizing illegal border crossings and expanding the Supreme Court. His top priorities are breaking the influence of corporations and addressing climate change. Steyer has spent millions pushing for Trump’s impeachment.

Elizabeth Warren, senator from Massachusetts.

Warren, 70, has become known for her long list of policy plans, including creating a wealth tax, canceling student loan debt for most borrowers and breaking up big technology companies. But she had been dogged by questions about how she would pay for Medicare for All. She released a plan on Friday.

Steve Bullock, Montana governor

Bullock, 53, is known as a pragmatist who was able to win Republican support for liberal priorities. He leads a state that Trump easily won in 2016. Bullock has emphasized campaign finance reform, while also pushing early childhood education and other policies aimed at reducing economic inequality.

Pete Buttigieg, South Bend, Ind., mayor

Buttigieg, 37, of Indiana, is new to national politics. The military veteran is the first openly gay, serious contender for his party’s presidential nomination. The youngest candidate in the race, Buttigieg has stressed his generational identity and focused on issues like climate change and economic opportunity.

Julián Castro, former HUD secretary

Castro, 45, was a rising political star during the Obama administration but struggled to find a role afterward. The former San Antonio mayor has called for overhauling the immigration system, including decriminalizing border crossings, and education policies like universal prekindergarten.

John Delaney, former member of Congress from Maryland

Delaney, 56, was elected to the House in 2012 as a “pragmatic idealist,” in his telling. He has visited every county in Iowa, but that hasn’t done much to improve his long-shot prospects. He has pitched himself as a bipartisan problem-solver, but has also endorsed liberal causes like universal health care.

Tulsi Gabbard, member of Congress from Hawaii

Gabbard, 38, was deployed to Iraq and currently serves as a major in the Hawaii Army National Guard. She has leaned on her background as a service member in making foreign policy her chief concern. Specifically, she is urging the United States to get out of foreign wars and focus on peacebuilding.

Kamala Harris, senator from California

Harris, 55, the former attorney general of California, has drawn notice in the Senate for her tough questioning of Trump’s cabinet nominees and Supreme Court nominee Brett Kavanaugh. Harris has offered middle-class tax cut legislation and has championed a liberal civil rights agenda in the Senate.

Marianne Williamson, author

Williamson, 67, the author of more than a dozen self-help and spirituality books, ran for Congress as an independent in 2014 and lost. She has proposed $100 billion in reparations for slavery, with $10 billion to be distributed annually over a decade for economic and education projects.

Andrew Yang, former tech exec

Yang, 44, says his experience working in Silicon Valley gave him an up-close look at the way automation could affect the economy in the years ahead. His solution? To give every American a “universal basic income” of $1,000 a month. Yang has highlighted issues like robotics and artificial intelligence.

Mark Sanford, former member of Congress from South Carolina

Sanford, 59, supported Trump in 2016 but eventually became one of his most vocal Republican critics in Congress. The former governor of South Carolina was marred during his second term by the disclosure of an extramarital affair. Sanford is using his campaign to push a debate about America’s mounting debt.

Donald Trump, president

Trump, 73, is heading into the race under the cloud of a House impeachment investigation centered on his dealings with Ukraine. He also faces other legal investigations. His main legislative accomplishment to date has been a sweeping tax cut that chiefly benefited corporations and wealthy investors.

Joe Walsh, radio show host

Walsh, 57, rode the Tea Party wave to Congress in 2010 and served one term in the House. He staunchly supported Trump in 2016 but has since broken with the president. He wants to reduce the national debt, restrain executive power, secure the border and defeat Trump, who he says “can’t be trusted.”

Bill Weld, former Massachusetts governor

Weld, 74, ran for vice president on the Libertarian Party ticket in 2016. He emerged as a vocal critic of Trump during the 2016 election and is presenting himself as a voice for alienated moderates and mainstream conservatives. He favors fiscal restraint, free trade and moderate immigration reform.