(CNN) In his first week as President, Donald Trump is taking executive actions at a rapid clip, scrawling his sawtooth autograph on documents he hopes will stake out a sharply conservative agenda over the next four years and beyond.
Shaping his administration's policy through orders and memoranda on everything from health care to oil pipelines to immigration, Trump is collecting evidence of campaign promises fulfilled.
But if he hopes to see his vows realized fully, the unilateral moves this week won't suffice; he'll need cooperation from Congress and buy-in from Republicans and Democrats alike to push forward with ideas he claims will reshape the American economy for the better.
Like presidents before him, Trump has issued a flurry of actions as an opening salvo to his government, denouncing on paper some of President Barack Obama's chief accomplishments: his signature health care law, his massive Pacific trade deal, and his decision to scuttle the Keystone XL oil pipeline.
Also like his predecessors, Trump will find his powers to enact major changes are limited. His executive moves alone can't roll back the Obama legacy. And just as his predecessor faced legal challenges to his executive power, Trump will likely confront resistance to his moves in court.
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"Every president encounters these challenges, every president has some executive actions struck down or limited by courts, but courts generally defer significantly to the president's power," said John Hudak of the Brookings Institution.
Trump's orders this week vary in scope. Most, however, won't prompt action right away.
An order on Obamacare -- signed hours after Trump was sworn into office -- issued a broad mandate for heads of federal agencies to "minimize the economic burden" of the health care law, but didn't recommend any single action that could roll back the Affordable Care Act's programs.
The document clarified that actions are only allowed to the "maximum extent permitted by law," which underscores that major changes to Obamacare, like the individual mandate, will require legislation. Lawmakers have begun the repeal process, but many are wary of removing the law without a clear replacement plan.
Speaking at a GOP retreat in Philadelphia on Thursday, Trump acknowledged that some Republicans in Congress were advocating a cautious approach toward repealing the Affordable Care Act. He said he'd discussed with House Speaker Paul Ryan delaying action for two years.
"I think we have no choice. We have to get it going," he said. "If we waited two years, it's going to explode like you've never seen an explosion. Nobody is going to be able to afford it. It's a disaster."
Trump's action on Wednesday ordering construction to begin on a border wall will require congressional partnership, too. The project is estimated to cost up to $15 billion, funds that lawmakers will need to approve. The White House said Thursday it had discussed a 20 percent tax on Mexican imports to fund the project, but called it only one idea of many.
Not all Republican lawmakers have endorsed Trump's combative approach toward Mexico. Several Republicans privately say they are worried that the new president is starting a trade war with one of the country's most significant trading partners -- and could drive up the debt in the process.
"He's going to start a war," said one senior GOP source who asked not to be named.
In other orders, Trump was merely reiterating the existing political reality.
Trump's executive order withdrawing the US from the Trans Pacific Partnership trade deal was largely a symbolic move -- the measure was never ratified, and never received a vote in Congress, and thus required no action on the part of the president to withdraw. Even if it was ratified, there was little likelihood that Trump would approve it.
An order halting hiring at non-military agencies contained wide exemptions for jobs "necessary to meet national security or public safety responsibilities," which is a broad definition. It also exempted military hiring, which accounts for a third of federal jobs.
Trump's order allowing the Keystone XL and Dakota Access pipelines to proceed was a shift in policy, but the projects are still a long way from getting started. Trump himself said the US would renegotiate the terms of the pipelines, which implies a lengthy process with several competing interests.
And a regulatory freeze was a near exact replica of executive orders that the past two Presidents have had their chiefs of staff issue at the beginning of their administrations. The move halts any item currently in the regulatory process -- a move that isn't a surprise given the change in administration.
"One of the functions of these executive instruments is to give instructions to different bits of federal bureaucracy," said Aziz Huq of the Law School at the University of Chicago. He suggested that the executive actions and orders need to be viewed separately.
"There are many elements of the orders that are well understood to give instruction to federal agencies," he said.
In some instances, Trump is "directing agencies on how to interpret the law," Huq said, as opposed to writing new policy.