Trump associates who have been sent to prison or faced criminal charges Rep. Chris Collins, an early Trump supporter, faces sentencing Friday.

Rep. Chris Collins, R-N.Y., the congressman who was once the first to stand up and endorse then-candidate Trump during the 2016 election, was sentenced to two years and two months in federal prison on Friday.

Having pleaded guilty to charges related to securities fraud conspiracy and making false statements, and resigning from his post last year, Collins is just the latest in a series of close allies and associates of President Trump to face the stain of a criminal record. In all, 14 Trump aides, donors and advisers have been indicted or imprisoned since the days when the first-time candidate promised that he would only hire "the best people."

Presidents are surrounded by tens of thousands of supporters and hire hundreds of aides into various jobs – so it may be inevitable that some tiny fraction of them will run afoul of the law. But experts say Trump is amassing a record unusual for an American president – in that so many senior advisers have come under legal scrutiny.

The count includes senior members of Trump’s campaign staff, including former campaign chair Paul Manafort and his deputy, Rick Gates – both snared on financial misdeeds in special counsel Robert Mueller investigation. Trump’s first national security adviser – Lt. Gen. Michael Flynn – pleaded guilty to lying to the FBI – though he has recently moved to retract his plea. His personal attorney, Rudy Giuliani, is under criminal investigation for his business relationship with two men arrested in an alleged campaign finance scheme, according to sources. Both Giuliani associates have pleaded not guilty.

White House did not respond to ABC News' request for comment and the Trump campaign declined to comment.

Collins is one of the two earliest Trump supporters in Congress – and both have recently been convicted in federal prosecutions. Former Rep. Duncan Hunter, R-Calif., who had the distinction of being the second congressman to endorse Trump, stepped down from his seat earlier this week, after pleading guilty last month to conspiring to misuse $250,000 of campaign funds for his personal expenses. The California Republican is slated to be sentenced in March.

At the time of Collins and Hunters' indictments in 2018, Trump responded in a tweet blaming then-Attorney General Jeff Sessions and the Justice Department for bringing investigations of "two very popular Republican Congressmen" to a "well publicized charge, just ahead of the Mid-Terms."

"Two easy wins now in doubt because there is not enough time," He added.

And Trump has seen some of his donors ensnared in criminal probes.

Washington-based lobbyist Sam Patten pleaded guilty to illegally funneling foreign money into Trump's inaugural committee as well and was sentenced to three years of probation, a $5,000 fine and 500 hours of community service. As the president's personal lawyer, Giuliani at that time downplayed Patten's association with Trump, saying "Trump has no idea who these contributors are."

New England Patriots owner Bob Kraft, a close personal friend of Trump's, a Mar-a-Lago member who gave $1 million to the inaugural committee, is currently fighting misdemeanor charges in Florida related to alleged solicitation of prostitution. Kraft has pleaded not guilty.

George Nader, a Lebanese-American businessman and lobbyist with ties to the Trump world and a key witness in the Mueller investigation, recently pleaded guilty to charges related to child sex trafficking and child pornography possession. He was also charged last month in connection to an alleged scheme to funnel millions of illegal campaign contributions to political entities supporting Clinton during the 2016 election.

California-based Imaaz Zuberi, who gave $900,000 to the Trump inaugural committee, was indicted last October for allegedly making illegal foreign straw donation, violating foreign lobbying laws and evading taxes. Last week, federal prosecutors added obstruction of justice to Zuberi's indictment, accusing him of taking "numerous steps" to thwart the federal criminal investigations upon learning of the investigation. Zuberi has pleaded guilty. Zuberi was also a major donor for Hillary Clinton and former President Barack Obama.

Trump is by no means the only president who has been associated with convicted criminals. The Watergate burglary, which led to Richard Nixon’s downfall, resulted in a number of Nixon’s associates, including his campaign operative G. Gordon Liddy, being convicted. Bill Clinton pardoned his brother, Roger, who was convicted of cocaine possession in the 1980s. And on his last day in office, Clinton made the controversial decision to pardon financier and major Democratic donor Marc Rich, who had fled overseas to escape indictment for alleged financial crimes. In 2009, a top donor to Democrats John Kerry, Hillary Clinton and Barrack Obama -- New York financier Hassan Nemazee –– was sent to prison after being convicted of financial crimes.

To Trump’s critics, though, the charges being brought against his advisers has been viewed as a symptom of something concerning. Watchdog group Citizens for Responsibility and Ethics in Washington's policy director Jennifer Ahearn said she worries about the “tone from the top.”

“Would he issue pardons to help these very people avoid the consequences of their actions?” she asked. “Would he interfere in Justice Department or other enforcement actions against them? These could be additional serious ethics problems on top of all the troubling conduct we've already seen."

But supporters of the president say he has been the target of unprecedented scrutiny – a phenomenon epitomized by the Mueller probe.

Larry Schweikart, an American historian and retired history professor at the University of Dayton who wrote a book called “48 Liberal Lies About American History,” said he viewed the Mueller indictments were a product of "asymmetrical" prosecution.

String of Trump associates indicted in the Mueller probe

Special counsel Mueller's 22-month-long investigation into Russian meddling in the 2016 presidential election, resulted in at least six convicted felons in the president's close orbit.

Manafort was found guilty on a slew of financial crime charges related to his lobbying work in Ukraine and is currently serving an 81-month prison sentence. Meanwhile, Gates, who had struck a plea deal early on in the case, was recently sentenced to 36 months probation and 45 days in jail after cooperating with the government as a key witness for nearly two years.

The president's former longtime fixer and personal attorney Michael Cohen is also serving three years in prison, after pleading guilty to making false statements to Congress in a case brought by Mueller's team as well as a separate campaign finance and and tax crime case brought by federal prosecutors in Manhattan.

Most recently, veteran GOP operative and longtime Trump adviser Roger Stone was found guilty on all seven counts related to his false statements to Congress, obstruction of justice and witness tampering, and is now awaiting sentencing.

And Gen. Flynn, who was among the first individuals to strike a plea deal with Mueller's team after being charged with making false statements to investigators, is now awaiting sentencing, which is scheduled for Jan. 28. Flynn is now looking to withdraw his guilty plea.

The Trump campaign's former foreign policy adviser George Papadopoulos, convicted of lying to investigators, spent two weeks in prison.

The days ahead

With several investigations actively targeting Trump associates, the trendlines for his administration show no signs of abating.

Prosecutors in the Southern District of New York indicted two associates of Trump personal attorney Rudy Giuliani -- Lev Parnas and Igor Fruman – accusing them of circumventing election laws that prohibit straw donations and foreign contributions to federal political campaigns, including a super PAC supporting President Trump's re-election campaign. Both men have pleaded not guilty in the case.

Federal prosecutors in Manhattan are also investigating whether there was any criminality in the business relationship between Giuliani and the two Florida men, who are also embroiled in the congressional impeachment inquiry as key players in Giuliani's efforts to investigate former Vice President Joe Biden in Ukraine, sources told ABC News. Parnas has been complying with at least some of House investigators' requests by submitting documents and data, while Fruman has yet to answer House investigators.

Last year, the president’s inaugural committee was hit with sweeping requests for documents from federal prosecutors in New York and the New Jersey attorney general’s office, and the status of that investigation remains unknown. In November, a lobbyist with close ties to Trump saw his firm hit with subpoenas for records.

Professor Nancy Kassop, of the political science department at the State University of New York at New Paltz and a researcher with the White House Transition Project, told ABC News she believes Trump is finding "such a large number of" criminally charged associates or compromised administration officials that have been forced to resign amid scandals most likely can be attributed to "exceptionally poor vetting, if any, during the hiring process."

Critics have called into question Trump team's vetting process for top officials during the early state of the administration, and last year leaked Trump transition vetting documents showed a host of top officials with problematic issues in their background that raised "red flags," according to Axios.

Some other experts, on the contrary, say recent past administrations have faced fewer criminal charges than Trump because prosecutors were not as aggressive.

"I don't think Trump is a particularly virtuous individual -- I just don't see him as being worse than some of his predecessors," said Paul Gottfried, an American historian and the editor-in-chief of Chronicles magazine.