Washington Gov. Jay Inslee entered the crowded race for the Democratic presidential nomination on Friday, hopeful that his focus on sweeping efforts to mitigate climate change will resonate with voters and draw sharp contrasts with the environmental policies of President Trump. He made his official announcement on the same day, with a rally at a solar plant in Seattle, with a speech focused on climate change and a promise to make it the country's "number-one priority."

"We know that fighting climate change can't be somewhere down, long down the page on a laundry list of our national things to do," Inslee said. "It requires building national mandate for bold and audacious action right now."

"I will put this simply," he went on to say. "If climate change isn't priority number one it's not going to get done, so I am saying this. I am pledging today if I am given this high honor, I will make fighting climate change the number-one priority of the United States of America."

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The popular two-term governor announced his White House bid with a campaign video published Friday morning that calls on Americans to join him in an endeavor to tackle "the most urgent challenge of our time."

"This crisis isn't just a chart or graph anymore. The impacts are being felt everywhere," Inslee, 68, said in the video. "We have an opportunity to transform our economy, run on 100 percent clean energy, that will bring millions of good paying jobs to every community across America, and create a more just future for everyone."

"I'm running for president because I am the only candidate who will make defeating climate change our nation's number one priority," he added.

Inslee, the first governor to launch a campaign for the White House this campaign cycle, joins one the most diverse and open Democratic primary fields in U.S. history. Nearly a dozen Democrats have declared their candidacy for president or launched presidential exploratory committees, including Sens. Bernie Sanders, Kirsten Gillibrand, Kamala Harris, Cory Booker and Elizabeth Warren; Hawaii Rep. Tulsi Gabbard; and former Housing and Urban Development (HUD) secretary Julián Castro.

Several others, like Vice President Joe Biden, former Texas Rep. Beto O'Rourke, Sen. Sherrod Brown of Ohio, former Colorado Gov. John Hickenlooper and former New York City mayor Michael Bloomberg, are also considering bids for the Democratic nomination.

With most 2020 Democrats throwing their support for the bold "Green New Deal" proposal introduced in early February by progressive Rep. Alexandria Ocasio-Cortez of New York, Inslee's spirited messaging on climate change has the potential to gain traction among Democratic primary voters and even prompt fellow contenders to discuss the issue more during the nomination process.

Who is Jay Inslee?

On the campaign trail, the Washington governor is likely to distinguish his support for federal action to reduce greenhouse gases and foster green energy jobs with the White House's controversial environmental decisions that have angered climate activists and scientists, including the abrupt withdrawal from the landmark Paris climate accords, the deregulation of the fossil fuel industry and the roll back of President Obama's "Clean Power Plan" initiatives.

Inslee is also expected continue rebuking Mr.Trump for deriding human-induced climate change and calling it a "hoax," despite scientists repeatedly rebuffing him for downplaying the assessment by the scientific community that the planet's changing climate is causing irreparable environmental damage.

During his second term, the Washington governor has been a frequent and vocal critic of the president, appearing on cable news to denounce Mr. Trump's governance style and teaming up with the state's attorney general, Bob Ferguson, to mount court challenges to some of his administration's policies, including the travel ban designed to bar immigration from predominantly Muslim countries.

In addition to climate change, Inslee will likely campaign on his advocacy for gun control measures, the growing economy in his deep-blue state, his role in the passage of a net neutrality bill and what he called "the best paid family leave and one of the best minimum wages" in the country.

But Inslee faces an uphill battle in expanding his name recognition across the country in a race that features high-profile senators and could also include the former vice president.

Before defeating the incumbent Republican attorney general to win Washington's governorship in 2012, Inslee served in Congress for an interrupted tenure of nearly 15 years. As the Representative for Washington's 1st Congressional district, he strongly opposed the war in Iraq and was one of the first lawmakers to call on the federal government to undertake sweeping policies to transform the American economy by ending its dependence on fossil fuels and investing heavily in renewable energy like solar and wind.

Inslee was born and raised in Seattle.

Ben Mitchell contributed to this report.