Under federal law, possession of even small amounts of marijuana is still a crime in the District. Federal law enforcement can still arrest anyone for possession in D.C., although local law enforcement (the Metropolitan Police Department) complies with local decriminalization of possession of up to 2 ounces by a person over age 21. But whether you’re 21 and under, or over 21, the government must not exceed constitutional prohibitions against unreasonable searches and seizures (whether seizure of a person or evidence of an alleged crime). The Fourth Amendment of the U.S. Constitution gives enhanced protection to preserving the sanctity of the home. Privacy in your home extends to all types of warrantless “searches,” whether the search is conducted in person by police, or through infrared technology. Your privacy might even be protected from warrantless surveillance flights above your property, depending on how common such flights are, if you maintain a “reasonable expectation of privacy” from such intrusions.
You can voluntarily relinquish your Fourth Amendment protections by volunteering to let government and enforcement authorities into your home. The main question in these cases is whether you voluntarily consented, or gave in to unlawful coercion. If the authorities forced you to comply with an unlawful search, you may have grounds to prevent the evidence from being used against you.
The circumstances of your case also impact the unlawfulness (or lawfulness) of the search. For example, use of infrared technology does not mitigate the intrusion, Kyllo v. United States, 553 U.S. 27 (2001), and a surveillance flight over a covered portion of your acreage still requires a warrant in most circumstances, Florida v. Riley, 488 U.S. 445 (1989). But the courts have allowed warrantless searches of garbage bags placed at the curb for pickup, asserting that the police did nothing more than what anyone on the street could have done lawfully, in California v. Greenwood, 486 U.S. 35 (1988), and have allowed police to bring drug-sniffing canines into a private driveway to sniff the outside of the garage door, in U.S. v. Holley (5th Cir. 2016). If the canine alerts police to the presence of contraband, warrants are obtained to seize the evidence in the garage.
Even the late U.S. Supreme Court Justice Antonin Scalia, a strict constructionist of the U.S. Constitution, wrote for the U.S. Supreme Court’s majority in Florida v. Jardines, 133 S. Ct. 1409, 569 U.S. ___ (2013), that a canine sniff of a homeowner’s front porch was an unconstitutional warrantless search. But the U.S. Court of Appeals for the Fifth Circuit reasoned that a driveway is not a porch, because the private home life of the individual does not extend into the driveway, and that a drug-sniffing canine is not sense-enhancing technology (on the order of Kyllo). Holley, supra. Holley filed a petition for certiorari on February 3, 2017.
Unusual circumstances in warrant execution and investigation also allow the government to chip away at the Fourth Amendment’s protections. One of the most relevant for the marijuana debate is the use of illegally-seized evidence in sentencing, that is, even when the Fourth Amendment prevents use of the evidence to determine guilt, if other evidence exists that convinces a jury to find guilt, the illegally-seized evidence can be used to increase a sentence—in some cases, to the same extent as if the illegally-seized evidence had been admitted at the trial. As the U.S. Court of Appeals for the Sixth Circuit emphasized:
[G]iven that disputed facts at sentencing need only be established by a preponderance of the evidence, see U.S.S.G. § 6A1.3, comment.; United States v. Herrera, 928 F.2d 769, 774 (6th Cir. 1991), rather than beyond a reasonable doubt, state officers now have the somewhat perverse incentive to rely more heavily on sentencing than trial to establish facts that may be of overriding importance in determining a defendant’s length of imprisonment—for example, the total amount of drugs involved in a criminal scheme. As a result, sentencing has to a significant extent replaced trial as the principal forum establishing the existence of certain criminal conduct. United States v. Nichols, 979 F.2d 402 (6th Cir. 1992).
Relief was afforded to criminal defendants, however, in Alleyne v. United States, 570 U.S. _____ (2013), in which the U.S. Supreme Court held that facts that aggravate the prescribed range of sentences to which a defendant may be exposed (e.g., such as possession of a firearm during commission of the offense) are not merely "sentencing factors" but "elements" of the offense(s) of which the defendant is accused, and, therefore, must be submitted to a jury and proven beyond a reasonable doubt.
Therefore, if the admission of illegally-seized evidence during sentencing aggravates the permissible range of sentences (by either lowering the minimum sentence, or increasing the mandatory sentence), the sentence is an unconstitutional violation of a defendant's right to jury trial. See Alleyne, supra.
If you have an arrest record for possession of marijuana, you may be eligible to have the record of the arrest sealed. The Criminal Record Sealing Act of 2006 opened a pathway to sealing for many former criminal defendants charged with “eligible misdemeanors,” such as possession, or felony failure to appear (the only “eligible felony”).