Biography | Maggie O'Neil

Education

Georgetown University Law Center (J.D., summa cum laude, 2018)
- Managing Editor, Georgetown Law Journal, Annual Review of Criminal Procedure
- Order of the Coif
- Francis E. Lucey, S.J. Award for Highest Academic Achievement in Graduating Class
Marquette University (B.A., summa cum laude, 2015)
- Phi Beta Kappa

Conspiracy

Challenging the Government’s Proof of Conspiratorial Intent, Part I: Rare Second Circuit Decision Overturning Guilty Verdict Shows Modern-Day Limits to Government’s Evidence of Conspiracy

Conspiracy charges are among the most potent instruments in the prosecutor’s toolkit. In a conspiracy case, the government need only prove that there was an illegal agreement, even if no crime occurred or could occur (such as in the case...

July 9, 2025Conspiracy

Challenging the Government’s Proof of Conspiratorial Intent, Part 2: Analysis of Mackey Decision Overturning Guilty Verdict Provides Fuel for Defense Attorneys

In recent months, the Second Circuit has frequently opined on issues related to the sufficiency of evidence for proving a defendant had the requisite knowledge of a conspiracy. This series of blog posts aims to synthesize these recent holdings, and...

July 9, 2025Fourth Amendment

Second Circuit Avoids Entering Debate Over Trespassory Searches, and Holds that Officers’ Use of an iPhone to View Contents of Automobile Through Tinted Windows is Not a Search

In United States v. Poller, the Second Circuit (Parker, Bianco, Nardini) held that an officer’s use of an iPhone camera to view the contents of an automobile through tinted windows was not a search because the defendant did not have...

February 20, 2025

Conspiracy

Challenging the Government’s Proof of Conspiratorial Intent, Part I: Rare Second Circuit Decision Overturning Guilty Verdict Shows Modern-Day Limits to Government’s Evidence of Conspiracy

July 9, 2025Conspiracy

Challenging the Government’s Proof of Conspiratorial Intent, Part 2: Analysis of Mackey Decision Overturning Guilty Verdict Provides Fuel for Defense Attorneys

July 9, 2025Fourth Amendment

Second Circuit Avoids Entering Debate Over Trespassory Searches, and Holds that Officers’ Use of an iPhone to View Contents of Automobile Through Tinted Windows is Not a Search

February 20, 2025Sentencing

Second Circuit Reiterates, in a Published Decision, that Defendant Is Bound By Decision to Decline Oral Pronouncement of Conditions of Supervised Release During Sentencing

In United States v. Lewis, the Second Circuit (per curiam) affirmed the judgment of conviction of Chanette Lewis, who had pleaded guilty to two counts of conspiracy to commit wire fraud in violation of 18 U.S.C. § 371. The Court...

January 3, 2025Fourth Amendment

Rare En Banc Second Circuit Says “Spread Eagle” Order Not a Search Over Spirited Dissents Decrying State of Fourth Amendment Jurisprudence

The Second Circuit, sitting en banc, reversed a panel decision holding that officers lacked reasonable suspicion to frisk defendant Calvin Weaver after a traffic stop. The en banc majority (Judge Nardini, who authored the opinion, Chief Judge Livingston, and Judges...

August 31, 2021Fourth Amendment

Second Circuit Reverses One Conviction for Lack of Venue, Affirms Others Despite Unlawful Warrant

In United States v. Purcell, the Second Circuit (Lynch, Pooler, and Park) considered the conviction of defendant Lavellous Purcell on five counts all arising out of his operation of a prostitution business. On appeal, Purcell argued that the warrants obtained...

September 3, 2020

Second Circuit Again Finds Plain Error in Use of “Motive to Lie” Jury Instruction When Criminal Defendants Take the Stand

In United States v. Solano, the Second Circuit (Kearse, Calabresi, and Carney) vacated and remanded a conviction for attempted possession of cocaine with intent to distribute on the grounds that the district court had committed plain error when it instructed...

July 30, 2020Fifth Amendment

As Second Circuit Affirms Conviction for Failure to Register as a Sex Offender, Judge Calabresi Questions “Non-Punitive” Nature of Registration Statutes

In a per curiam opinion, United States v. Diaz, the Second Circuit (Calabresi, Chin, and Carney) held that the Sex Offender Registration and Notification Act (“SORNA”), 18 U.S.C. § 2250(a), does not permit a defendant to collaterally attack his or...

July 23, 2020

All Posts

Sentencing

Second Circuit Reiterates, in a Published Decision, that Defendant Is Bound By Decision to Decline Oral Pronouncement of Conditions of Supervised Release During Sentencing

January 3, 2025Fourth Amendment

Rare En Banc Second Circuit Says “Spread Eagle” Order Not a Search Over Spirited Dissents Decrying State of Fourth Amendment Jurisprudence

August 31, 2021Fourth Amendment

Second Circuit Reverses One Conviction for Lack of Venue, Affirms Others Despite Unlawful Warrant

September 3, 2020

Second Circuit Again Finds Plain Error in Use of “Motive to Lie” Jury Instruction When Criminal Defendants Take the Stand

July 30, 2020Fifth Amendment

As Second Circuit Affirms Conviction for Failure to Register as a Sex Offender, Judge Calabresi Questions “Non-Punitive” Nature of Registration Statutes

July 23, 2020

News

April 17, 2026

Firm Achieves Significant Lanham Act Win for Johnson & Johnson

On April 17, 2026, Patterson Belknap secured a significant victory for our clients, Johnson & Johnson and Janssen Biotech, Inc. (“J&J”), when the U.S. District Court for the Southern District of New York denied a preliminary injunction in a Lanham...

June 13, 2022

Patterson Belknap Files Lawsuit On Behalf of Family of Tyshon Jones

May 10, 2022

Firm Secures $2 Billion Jury Verdict in Trade Secret Case for Appian

April 17, 2026

Firm Achieves Significant Lanham Act Win for Johnson & Johnson

June 13, 2022

Patterson Belknap Files Lawsuit On Behalf of Family of Tyshon Jones

May 10, 2022

Firm Secures $2 Billion Jury Verdict in Trade Secret Case for Appian

November 18, 2021

Firm Secures Major Patent Litigation Win for Janssen Pharmaceuticals

November 18, 2021

Firm Secures Major Patent Litigation Win for Janssen Pharmaceuticals

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Blog Posts: Second Circuit Criminal Law Blog

Challenging the Government’s Proof of Conspiratorial Intent, Part I: Rare Second Circuit Decision Overturning Guilty Verdict Shows Modern-Day Limits to Government’s Evidence of Conspiracy

Challenging the Government’s Proof of Conspiratorial Intent, Part 2: Analysis of Mackey Decision Overturning Guilty Verdict Provides Fuel for Defense Attorneys

Second Circuit Avoids Entering Debate Over Trespassory Searches, and Holds that Officers’ Use of an iPhone to View Contents of Automobile Through Tinted Windows is Not a Search

Challenging the Government’s Proof of Conspiratorial Intent, Part I: Rare Second Circuit Decision Overturning Guilty Verdict Shows Modern-Day Limits to Government’s Evidence of Conspiracy

Challenging the Government’s Proof of Conspiratorial Intent, Part 2: Analysis of Mackey Decision Overturning Guilty Verdict Provides Fuel for Defense Attorneys

Second Circuit Avoids Entering Debate Over Trespassory Searches, and Holds that Officers’ Use of an iPhone to View Contents of Automobile Through Tinted Windows is Not a Search

Second Circuit Reiterates, in a Published Decision, that Defendant Is Bound By Decision to Decline Oral Pronouncement of Conditions of Supervised Release During Sentencing

Rare En Banc Second Circuit Says “Spread Eagle” Order Not a Search Over Spirited Dissents Decrying State of Fourth Amendment Jurisprudence

Second Circuit Reverses One Conviction for Lack of Venue, Affirms Others Despite Unlawful Warrant

Second Circuit Again Finds Plain Error in Use of “Motive to Lie” Jury Instruction When Criminal Defendants Take the Stand

As Second Circuit Affirms Conviction for Failure to Register as a Sex Offender, Judge Calabresi Questions “Non-Punitive” Nature of Registration Statutes

Second Circuit Reiterates, in a Published Decision, that Defendant Is Bound By Decision to Decline Oral Pronouncement of Conditions of Supervised Release During Sentencing

Rare En Banc Second Circuit Says “Spread Eagle” Order Not a Search Over Spirited Dissents Decrying State of Fourth Amendment Jurisprudence

Second Circuit Reverses One Conviction for Lack of Venue, Affirms Others Despite Unlawful Warrant

Second Circuit Again Finds Plain Error in Use of “Motive to Lie” Jury Instruction When Criminal Defendants Take the Stand

As Second Circuit Affirms Conviction for Failure to Register as a Sex Offender, Judge Calabresi Questions “Non-Punitive” Nature of Registration Statutes

News

Firm Highlights

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Maggie O'Neil

Maggie O'Neil

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Education

Blog Posts: Second Circuit Criminal Law Blog

Challenging the Government’s Proof of Conspiratorial Intent, Part I: Rare Second Circuit Decision Overturning Guilty Verdict Shows Modern-Day Limits to Government’s Evidence of Conspiracy

Challenging the Government’s Proof of Conspiratorial Intent, Part 2: Analysis of Mackey Decision Overturning Guilty Verdict Provides Fuel for Defense Attorneys

Second Circuit Avoids Entering Debate Over Trespassory Searches, and Holds that Officers’ Use of an iPhone to View Contents of Automobile Through Tinted Windows is Not a Search

Challenging the Government’s Proof of Conspiratorial Intent, Part I: Rare Second Circuit Decision Overturning Guilty Verdict Shows Modern-Day Limits to Government’s Evidence of Conspiracy

Challenging the Government’s Proof of Conspiratorial Intent, Part 2: Analysis of Mackey Decision Overturning Guilty Verdict Provides Fuel for Defense Attorneys

Second Circuit Avoids Entering Debate Over Trespassory Searches, and Holds that Officers’ Use of an iPhone to View Contents of Automobile Through Tinted Windows is Not a Search

Second Circuit Reiterates, in a Published Decision, that Defendant Is Bound By Decision to Decline Oral Pronouncement of Conditions of Supervised Release During Sentencing

Rare En Banc Second Circuit Says “Spread Eagle” Order Not a Search Over Spirited Dissents Decrying State of Fourth Amendment Jurisprudence

Second Circuit Reverses One Conviction for Lack of Venue, Affirms Others Despite Unlawful Warrant

Second Circuit Again Finds Plain Error in Use of “Motive to Lie” Jury Instruction When Criminal Defendants Take the Stand

As Second Circuit Affirms Conviction for Failure to Register as a Sex Offender, Judge Calabresi Questions “Non-Punitive” Nature of Registration Statutes

Second Circuit Reiterates, in a Published Decision, that Defendant Is Bound By Decision to Decline Oral Pronouncement of Conditions of Supervised Release During Sentencing

Rare En Banc Second Circuit Says “Spread Eagle” Order Not a Search Over Spirited Dissents Decrying State of Fourth Amendment Jurisprudence

Second Circuit Reverses One Conviction for Lack of Venue, Affirms Others Despite Unlawful Warrant

Second Circuit Again Finds Plain Error in Use of “Motive to Lie” Jury Instruction When Criminal Defendants Take the Stand

As Second Circuit Affirms Conviction for Failure to Register as a Sex Offender, Judge Calabresi Questions “Non-Punitive” Nature of Registration Statutes

News

Firm Highlights