Mike Pompeo Eric Thayer | Reuters

President Donald Trump's massive staff shakeup in March ushered in a new chapter for his presidency — one that could bring seismic changes to America's economic and foreign policy. In less than four weeks, the Trump administration saw the replacements, either through resignation or removal, of Secretary of State Rex Tillerson, Director of the National Economic Council Gary Cohn and National Security Advisor Lt. Gen. H.R. McMaster. Trump characterized the tumultuous period for White House job security as being part of a larger plan. "We're getting very close to having the Cabinet and other things that I want," Trump said after Tillerson was fired March 13. The White House did not immediately respond to CNBC when asked what the new staff changes could mean for Trump's second year in office. While each of the erstwhile officials brought unique skill sets and worldviews to the Trump administration, all three appointments chafed against Trump's views and personality in distinct ways. The new recruits diverge from their predecessors on ideology, experience and style. Here's how:

Tillerson vs. Pompeo

Reports of Tillerson's acrimonious relationship with Trump were a near-constant feature of the Texas oilman's tenure in the White House. Their bad blood may have boiled over following a White House leak that claimed Tillerson called Trump a "moron." But both men also held different views on policy matters. Tillerson clashed with Trump over the president's decision to withdraw from the Paris climate change agreement, for instance. And Trump publicly rebuked him in October over his approach to North Korea. The president tweeted that his top diplomat was "wasting his time" trying to communicate with Kim Jong Un. Trump tweet Rocket Man Citing a senior State Department official, NBC News reported that Tillerson learned of his firing on March 13 only after Trump tweeted his congratulations to Tillerson's appointed successor, CIA Director Mike Pompeo. Trump tweet Pompeo Pompeo's policy views appear to align much more closely with Trump's, especially on Russia. Pompeo echoed the White House position that Russian efforts to interfere in the 2016 presidential election had no effect on the outcome. But the document he cited — a report from the Office of the Director of National Intelligence — said the intelligence community "did not make an assessment of the impact" of Russian meddling.

Outgoing U.S. Secretary of State Rex Tillerson makes a statement on his departure from the State Department March 13, 2018 at the State Department in Washington, DC. Getty Images

Tillerson, on the other hand, said in February that Russia is already interfering in the 2018 midterm elections. One of Tillerson's final acts in the Trump administration was to quickly accept the conclusions of U.S. and British intelligence that Russia likely carried out the attempted assassination of an ex-Russian spy living in London. Tillerson said Russia was "clearly" behind the nerve agent attack long before Trump himself addressed it. Pompeo has also firmly established himself as a critic of the Obama-era Iran nuclear deal, which Trump has called "the worst deal ever" and sought to dismantle. But the biggest difference between Pompeo and Tillerson may be based not on policy, but on the ability to run a government agency. Tillerson had no prior diplomatic experience when he left his job as the CEO of Exxon Mobil to join the Trump administration. Pompeo, however, boasts decades of experience in politics, and could be better suited to run the State Department for that reason, The Atlantic argued.

Cohn vs. Kudlow

President Donald Trump praises departing economic adviser Gary Cohn (L) during a Cabinet meeting at the White House, Washington, March 8, 2018. Kevin Lamarque | Reuters

Wall Street rejoiced when Trump picked Cohn as his top economic advisor. Likewise, it lamented his resignation in March. A former Goldman Sachs executive, Cohn supported lowering taxes, limiting regulations and creating a more hospitable economic climate for corporations — all policies that thrilled finacial markets. Trump had long established himself as a business-friendly candidate, and Cohn's appointment appeared to follow through on that commitment. Trump and Cohn reached an impasse, however, after the president announced broad, global tariffs on imports of steel and aluminum in March. A free-trade advocate, Cohn had argued against tariffs in a February meeting with the president and industry executives, according to a person in the room. He resigned less than a week after Trump announced the tariffs.

Larry Kudlow Scott Mlyn | CNBC

But Cohn's replacement, longtime CNBC pundit Larry Kudlow, shares many of Cohn's economic views. Like Cohn, Kudlow is pro-free trade and pro-tax cuts, and he criticized Trump's protectionist reflexes just days before the president asked him to join the administration. Kudlow also informally advised Trump during his campaign. Kudlow's main distinction from Cohn is his friendship with Trump. Kudlow and Trump are both former television hosts and personal friends. Kudlow has also indicated a willingness to bend in Trump's direction on trade. But Kudlow could still put up a fight as the director of Trump's National Economic Council, if his recent tweets are any indication: Kudlow Watch Milton Friedman Refute Steel Protectionists Back in 1978

McMaster vs. Bolton

National Security Adviser H.R. McMaster speaks at the United States Holocaust Memorial Museum in Washington, March 15, 2018. Brendan McDermid | Reuters

McMaster, an accomplished Army general known for his searing analysis of military strategy during the Vietnam War, drew praise from Republicans and Democrats alike as a solid choice to become Trump's national security advisor. However, the announcement on Thursday that former U.N. Ambassador John Bolton would replace McMaster received a very different response. "You can say one thing for the former UN Ambassador," wrote retired Army Lt. Col. Daniel L. Davis in an op-ed for CNBC. "He has been consistent throughout his career. Consistently wrong, that is." Bolton, who served under President George W. Bush's administration, is known for his hawkish military views. Even in areas where McMaster and Bolton ostensibly agree, the new national security advisor appears to take a more uncompromising stance. While McMaster has called the nuclear deal with Iran "fundamentally flawed," for instance, CNN reported in October that Democratic lawmakers "sensed" that the general was not willing to end the entire agreement.

New national security adviser John Bolton speaking at Capitol Hill on November 8, 2017. Getty Images