Both are forms of national emergency declarations, but the primary difference is the scope and funding for each order.

"This epidemic is a national health emergency," he said. "Nobody has seen anything like what is going on now."

He added: "As Americans, we cannot allow this to continue. It is time to liberate our communities from this scourge of drug addiction. Never been this way. We can be the generation that ends the opioid epidemic. We can do it."

Trump, through the Public Health Services Act, directed his acting secretary of health and human services to declare a nationwide health emergency, a designation that will not automatically be followed by additional federal funding for the crisis, according to a senior White House official.

Instead, the order will expand access to telemedicine in rural areas, instruct agencies to curb bureaucratic delays for dispensing grant money and shift some federal grants towards combating the crisis.

If Trump had used the Stafford Disaster Relief and Emergency Assistance Act, the federal government would have been able to immediately tap into funds from the Federal Emergency Management Agency's Disaster Relief Fund to combat opioids. The Stafford Act, though, has traditionally been used to provide recovery money to natural disasters, most recently from Hurricanes Maria, Irma and Harvey.

Funding

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Both designations come with pluses and minuses, experts and senior administration officials told CNN.

The nationwide health emergency that Trump ordered is more tailored and directed, but comes with less immediate action.

Senior White House officials told CNN that they will follow up this order by working with Congress to fund the Public Health Emergency Fund and to increase federal funding in year-end budget deals currently being negotiated in Congress. But both of those avenues are far from guaranteed, especially given all the other issues on Congress' plate.

By using the Stafford Act, Trump would have taken a dramatic step and immediately provided the federal government with money earmarked for natural disasters to combat the issue.

But both Trump and Obama administration officials say that designation would have been too broad and put an undue burden on the Federal Emergency Management Agency's Disaster Relief Fund, a fund already cash strapped by recovery efforts from the three major hurricanes that hit the United States this year.

Using FEMA funds to combat the opioid crisis would be "a little bit like asking an engineer to bake a cake," said Rafael Lemaitre, the former communications director for the White House Drug Policy Office under President Barack Obama.

"I do think the Public Health Service Act is more appropriate route to take than the Stafford Act designation," he said. "I worked at FEMA for two years and dealt with multiple disasters. The Stafford Act is not structured to deal with a long term, complicated public health crisis like the opioid crisis."

Tom Coderre, a former senior official in Obama's Substance Abuse and Mental Health Services Administration office at HHS, echoed that sentiment.

"One of the things that I think is the most beneficial part of having a public health emergency is you really can marshal public support and then you can bring all the resources of the federal government to bear on it, bringing people from all of the agencies to combat the issue," he said.

Though both Lemaitre and Coderre said this step was important, both agreed that it was not, in Lemaitre's words, a "silver bullet solution to the opioid crisis." That, they said, would be additional funding from Congress.

"A smarter play here would be for the administration to move beyond this declaration and pass the billions in funding needed to address this crisis. That is how you move the needle on this," Lemaitre said.

Fight against opioids

There are also concerns in the treatment community about how other actions by the Trump administration -- namely efforts to repeal Obamacare and strip funding from Medicaid -- would adversely impact the fight against opioids.

Coderre called efforts to repeal and replace Obamacare, the sweeping Obama-era health care law that mandates drug treatment services, the "elephant in the middle of the East Room today."

Trump's order on Thursday will rely heavily on the presidential commission he convened earlier this year, which in their interim report urge the President to use either the Public Health Services Act or the Stafford Act to declare a state of emergency.

"The first and most urgent recommendation of this commission is direct and completely within your control. Declare a national emergency under either the Public Health Service Act or the Stafford Act," wrote the commission led by New Jersey's Republican Gov. Chris Christie. "With approximately 142 Americans dying every day, America is enduring a death toll equal to September 11th every three weeks."

Christie heralded Trump's announcement by noting that the step was recommended by his commission.

But concerns remain about how Trump will follow through on the nationwide health emergency declaration.

"I hope the Trump administration follows through without delay to use this order to provide relief to the millions of families suffering from this crisis," said Rep. Marcy Kaptur, an Ohio Democrat. "We cannot afford to wait months between an announcement and action."