(CNN) Outside groups aligned with Senate Majority Leader Mitch McConnell have launched a three-pronged attack on Republican Rep. Doug Collins' professional record, attempting to portray him as weak on crime in order to doom his Senate campaign in Georgia against a GOP incumbent.

The Senate Leadership Fund (SLF) and One Nation spent nearly $2 million on television, radio and digital ads from late February until mid-March, according to a spokesman for the groups, revealing that they are deeply concerned about Collins, one of President Donald Trump's strongest defenders in Congress , running against Republican Sen. Kelly Loeffler , and willing to spend what it takes to try and take him down.

The National Republican Senatorial Committee has warned that Collins' bid jeopardizes the party's chances to hold onto the seat — one of two Senate seats in the state in play this year — and keep the Senate majority, while making it harder for Trump to carry the Peach State in the fall. Collins has dismissed the GOP groups' alarms and attacks as scare-tactics and lies meant to protect Loeffler, who was appointed to the position late last year by Gov. Brian Kemp to fill the seat left by Sen. Johnny Isakson's resignation. In addition to benefiting from the outside groups' attacks on Collins, Loeffler has also committed to spending $20 million of her own money on the race.

"Money is not going to buy this seat," Collins told CNN this week. "They have a candidate who doesn't relate to Georgia. They have a candidate that was picked by a governor and now Georgians are going to get to actually pick their next senator, which will be me."

Collins claims his polling still shows him ahead for the November election despite millions spent against him. But the Congressman has recognized that the onslaught of ads are taking a toll. Collins spent a good portion of a 40-minute video released last week on Facebook refuting the attacks on his record and urging his supporters to donate to his campaign.

Record as defense attorney

The outside groups have targeted Collins' work as a defense attorney in Georgia, where he represented clients charged with various crimes between 2007 and 2012. In one of the SLF ads, the narrator says Collins was "fighting to get bad guys out of jail." The spot cites a 2009 case in Hall County Georgia in which three men were found guilty of armed robbery.

A CNN review of over 150 court cases during those years when he was in active practice shows that the case was an outlier in Collins' legal career, in which he represented clients with a wide array of legal issues. Most of Collins' cases regarded nonviolent and drug offenses, including a gamut of traffic violations, driving under the influence, theft, obstructing an officer and possession of marijuana, methamphetamines and cocaine. Other clients were charged with public drunkenness, underage drinking and criminally trespassing. He represented a few clients dealing with divorce.

A minority of the cases reviewed by CNN involved violent crimes. He had 21 cases concerning battery, 10 of them alleged violations of the Family Violence Act, and three clients facing additional charges of 3rd degree-child cruelty. Most of the clients in those 21 cases pleaded no-contest or were found guilty of the battery charges.

Collins also was appointed by the court to defend at least one client accused of child molestation, but his law partner took it over when it was bound over to Superior Court.

Collins defended his legal practice based in Hall County, where he was born, raised and still lives, saying that it was an outgrowth of his work as a Baptist pastor. Before his election to Congress in 2012, Collins served a tour in Iraq as a chaplain in the Air Force Reserve.

"In my faith perspective, I believe that Christ stood with me on my worst day," Collins said. "How can I not stand with people on their worst day? It doesn't mean that I condone what they do."

Collins said that he earned his law degree relatively late in life and wanted to make a living. He claimed he was assigned to almost all of his cases, including the clients referenced in the SLF ad, and that the vast majority of his cases ended in no-contest pleas or guilty verdicts. He argued that attacking a defense attorney for doing his job was "a desperate attempt by them to paint an honorable profession in a way that can scare people."

"Everyone deserves an attorney to go through the process," said Collins. "There is nothing nefarious here about wanting to be a defense attorney. I just wanted to be the best attorney that I could be to help people."

In response, SLF communications director Jack Pandol said, "It's not a surprise Rep. Collins didn't want voters to learn the truth about his career letting criminals off the hook."

Record as a legislator

The attacks on his legal work are part of a broader effort by supporters of Loeffler to tarnish Collins' record as weak on crime. The ads also go after his bipartisan work on criminal justice legislation at the state and federal level, calling him a "criminal's friend" and "conservative's nightmare." The outside groups contend that Collins as a state legislator helped write a bill in the 2007-2008 session with then-Democratic state Rep. Stacey Abrams "to let some convicted murderers avoid the death penalty." They also claim that in Congress Collins drafted a bill that would've allowed some sex offenders to work toward an early release.

Collins' campaign said that the assertions are false. Collins said it was a "blatant lie" that a bill he supported in the state legislature let off murderers. His campaign noted it instead proposed changing the standard of proof in a "narrow set of death penalty cases" in which the court considers a defendant's mental incapacity.

In Congress, Collins did draft legislation that allowed some offenders to earn credits that would reduce their sentences and place them on community supervision, home confinement or in a halfway house, through participation in rehabilitation programs designed to reduce recidivism rates. The bill laid the groundwork for the First Step Act , which Collins also introduced and sponsored, and was ultimately signed into law by Trump and touted by the President's reelection campaign in a Super Bowl ad. As Congress revised the bill, the First Step Act expanded the number of ineligible prisoners to make sure certain offenders were not eligible for the credits, such as first-time offenders relating to certain activities involving material containing child pornography.

"This is part of the process of working to see what you can get done," Collins said. "They're attacking me on the same bill that Mitch McConnell voted for."

"I think you see the political angle here," he added.

Stephen Lawson, a spokesman for Loeffler's campaign told CNN that the senator "supports President Trump's criminal justice reforms."

"She strongly opposes Doug Collins' appalling record as a trial lawyer who fought to secure shorter sentences for domestic abusers and drug dealers, and as a career politician who teamed up with liberal Stacey Abrams to cut prison time for violent offenders," he added.

Are the attacks working?

A Georgia GOP strategist not working for either Collins or Loeffler told CNN that the attacks on Collins' record in government have fallen flat with Republicans since other high-profile Republicans in Congress and Georgia also supported the criticized legislation.

Collins is also viewed as a steadfast ally of Trump, particularly after serving as the top Republican on the Judiciary Committee during the House impeachment hearings last year. Collins votes with Trump 97.5% of the time, according to the website FiveThirtyEight.

The strategist said that ads attacking Collins' career as a defense attorney could prove more effective. "What they were doing wasn't working," said the strategist. "And so moving on to this makes sense to see if it sticks."

Jay Williams, another Republican strategist in Georgia, said the coronavirus outbreak sweeping the world is causing people to swiftly reevaluate their priorities, adding that what matters now may not matter months from now when voters go to the polls.

"I think anytime you can get on TV with a negative message and are able to put significant resources behind it, it's effective," said Williams. "If the coronavirus wasn't all the world was consumed with right now, I can see it getting more traction."

The special election will not have a typical party primary but a melee with candidates from all parties on the same ballot. It would go to a two-person runoff in January if no candidate reaches a majority of the vote.

Collins predicted that the November 3 election would turn to a runoff between him and a Democrat.

"They were doing this to try to keep me out of the race," Collins said. "And that didn't work."

This story has been updated to include additional developments Friday.