Vivek Ramaswamy, a wealthy newcomer in politics who aligned himself with Trump, has decided to step back from his campaign.

A self-funded entrepreneur, Mr. Ramaswamy reached the height of his popularity in late August but faced a decline under attacks from his opponents. Following his withdrawal post the Iowa caucuses, he expressed support for Donald J. Trump.

Vivek Ramaswamy, a 38-year-old entrepreneur and political novice who briefly gained attention for his bold policy proposals and overconfidence, has withdrawn from the race for the Republican White House nomination following a disappointing fourth-place finish in the Iowa caucuses.

Expressing regret over not delivering the anticipated surprise, Ramaswamy endorsed former President Donald J. Trump for the White House during a statement in Des Moines on Monday night. Despite initially being an unlikely contender, Ramaswamy closely aligned himself with Trump, pledging support even in the face of potential legal issues and promising a pardon if elected.

However, just two days before the Iowa caucuses, Trump's campaign turned against Ramaswamy, labeling him a fraud and urging voters to reject him. This marked a shift from months of warmth between the two figures.

As the Harvard-educated Ramaswamy continued his campaign, he embraced apocalyptic conspiracy theories, alleged a "system" blocking Trump's return to office, and propagated the unfounded theory of "replacement," falsely claiming Democrats aimed to replace white people with immigrants of color.

Ramaswamy's opening strategy emphasized his superior understanding of the Constitution and civil service laws, promising to take Trump's America First agenda even further. This included executive orders to immediately eliminate the Department of Education, F.B.I., and Internal Revenue Service, a 75 percent reduction in the federal workforce through mass layoffs without congressional approval, and scaling back foreign military commitments.

While his isolationist foreign policy became a target for criticism, Ramaswamy's bleak portrayal of Millennial and Generation Z voters as "starved for purpose, meaning, and identity" surprisingly resonated with older voters. In the end, facing challenges and controversy, Ramaswamy exited the race, throwing his support behind former President Trump.

During debates, Ramaswamy didn't hold back in engaging with fellow Republican contenders not named Trump. He openly ridiculed Gov. Ron DeSantis of Florida, alleging he wore high heels on his boots. He referred to Nikki Haley, the former South Carolina governor, as a pawn for China and the defense industry. Ramaswamy didn't spare the entire field, accusing them of being mere puppets controlled by wealthy financiers backing their super PACs. He even went as far as branding the GOP as a "party of losers."

Initially, unconventional tactics gave a boost to a businessman, Vivek Ramaswamy, who lacked prior elective office experience and was known to only a limited portion of the electorate familiar with his writings criticizing "Woke Capitalism" and promoting investment strategies focused on environmental progress and social consciousness. He garnered attention at the Iowa State Fair, showcasing his unique approach by rapping to an Eminem recording.

Ramaswamy's support among Republican primary voters surged to 11.6 percent in a composite of national polling on the day of the first Republican debate, securing him a third-place position, just behind Mr. DeSantis and well ahead of other contenders. However, as he sought attention and sometimes stretched the truth, he faced backlash from rivals, causing a slip in the polls.

During the second Republican primary debate in September, Nikki Haley expressed her frustration, stating, “every time I hear you, I feel a little bit dumber.” The tension escalated in the third debate in November, with Haley referring to Ramaswamy as “just scum” after he accused her of hypocrisy regarding China due to her daughter's use of TikTok.

By November, Haley had surpassed Ramaswamy for third place in national polling. Despite intensive campaigning in New Hampshire and numerous events, Ramaswamy couldn't regain momentum. Privately, he had shared with supporters his strategy of aligning with Trump, hoping the former president's legal battles would lead to his withdrawal, making Ramaswamy the logical choice for Trump's ardent supporters. However, with Trump firmly stating he would not be forced out even with a conviction, Ramaswamy's strategy and self-funding became unsustainable, leading to his withdrawal from the race.