The biggest patent reform in 60 years. Signed into law on September 16, 2011, the Leahy-Smith America Invents Act (AIA) reshaped American patent law in ways that, more than anything else, gave defendants the modern tools they have today.
For defendants, the AIA matters because it created the post-grant review system — IPR, PGR, and supplemental examination — and tightened a handful of procedural rules that NPEs had been exploiting. This is the AIA in plain English, focused on the parts that matter for defending against a patent assertion.
The big change: first-inventor-to-file
Pre-AIA, the United States used a first-to-invent system. The first person to invent something owned the patent rights, even if a later inventor filed first. Disputes about priority went to expensive interference proceedings.
Post-AIA, the US uses first-inventor-to-file (effective for applications filed on or after March 16, 2013). The first inventor to file the application wins — period. Interferences are gone, replaced by derivation proceedings (rare, only for cases where the second filer derived the invention from the first).
For defendants, first-inventor-to-file matters in two practical ways:
- Priority dates are simpler. No more "I invented this earlier in my notebook." The filing date is everything.
- Prior art is more comprehensive. Anything publicly available before the filing date qualifies — including filings by others.
Post-grant review (the big defendant win)
The AIA created three new USPTO proceedings, all administered by the Patent Trial and Appeal Board (PTAB):
Inter Partes Review (IPR)
Available for any patent more than 9 months after issue. Limited to § 102 / § 103 grounds based on patents and printed publications. Rapid (12-month statutory deadline). Lower burden of proof than district court (preponderance vs. clear-and-convincing). Estoppel applies after final written decision.
This is the workhorse defendant tool. Most patents that get aggressively challenged at the PTAB lose at least one claim. Cost: $200k-$500k vs. $3M-$5M for district-court invalidity.
Post-Grant Review (PGR)
Broader than IPR — any patentability ground (§ 101, § 102, § 103, § 112). Available only within 9 months of patent issuance. Rare in practice but powerful when applicable.
Supplemental examination
A patent owner-only proceeding. Lets a patent owner submit information to the USPTO to "cure" potential inequitable-conduct issues. Doesn't help defendants directly but matters for understanding patent owner strategy.
Patent reviews → covers IPR, PGR, and reexamination in detail.
Joinder reform
Pre-AIA, NPEs would file a single complaint naming dozens of unrelated defendants — companies that happened to use products that allegedly infringed the same patent, but had no other connection. This let the troll save filing fees, force common discovery, and pressure many defendants at once.
The AIA changed Rule 20-style joinder for patent cases. Defendants can now be joined only when the claims arise from "the same transaction, occurrence, or series of transactions or occurrences relating to the making, using, importing into the United States, offering for sale, or selling of the same accused product or process."
Translation: NPEs can no longer mass-sue 50 unrelated defendants in a single complaint. They can still file 50 separate complaints — and many do — but the unified discovery and consolidated pressure are gone.
Best mode
Pre-AIA, failure to disclose the best mode of practicing the invention could invalidate a patent. Post-AIA, best mode is still required to obtain a patent, but failure to disclose best mode is no longer a basis for invalidating a granted patent in litigation.
Net effect: one fewer invalidity defense for defendants. A small loss compared to the IPR/PGR gain.
False marking
Pre-AIA, anyone could sue under the false-marking statute and recover penalties for products marked with expired or inapplicable patent numbers. The AIA narrowed this to competitive injury plaintiffs only. Effectively ended a wave of opportunistic false-marking suits.
This isn't a defendant tool against assertion — it's a removal of a litigation pathway altogether.
Prior art expansion
Post-AIA § 102 expanded what counts as prior art:
- Public use anywhere in the world. Pre-AIA was limited to US use; post-AIA is global.
- On-sale anywhere. Same expansion.
- Otherwise available to the public. Open-ended catch-all that captures online disclosures, conference talks, etc.
Net effect: stronger prior art for defendants. A 1985 Japanese-language paper now anticipates a US patent if it discloses the invention; pre-AIA the geographic scope was narrower.
Prior art and § 102 → covers the post-AIA standard.
What the AIA didn't do
The AIA was substantial but didn't address several defendant-side concerns:
- Cost asymmetry. Filing a complaint is still cheap; defending is still ruinous. AIA didn't touch the cost structure of litigation itself.
- Venue. Pre-AIA, plaintiffs flocked to plaintiff-friendly venues (Eastern District of Texas). The AIA didn't fix venue; TC Heartland v. Kraft (2017) did.
- Fee-shifting. § 285 was untouched. Octane Fitness v. ICON Health (2014) lowered the bar for fee awards two years later.
The AIA was thus a partial victory. The full defendant-side toolkit emerged from a combination of the AIA + Alice (2014) + Octane (2014) + eBay (2006, with NPEs increasingly absorbing it through the 2010s) + KSR (2007) + TC Heartland (2017).
What it means for defendants today
Most modern defendant strategy depends on AIA-era tools:
- IPR for invalidity. (Patent reviews)
- § 102 / § 103 in district court. Strengthened by post-AIA prior-art definitions. (Prior art, Obviousness)
- Resistance to mass joinder. Each defendant gets their own case.
A defendant operating today has materially more tools than one operating in 2010, primarily thanks to the AIA. The frustrating part: those tools are still expensive to use. The AIA didn't make defense free; it made defense possible. (See the litigation lifecycle for where each AIA-era tool actually fires.)
Bottom line
The AIA was the structural reform that gave defendants the IPR system, expanded prior-art rules, and ended NPE mass-joinder tactics. Most modern defendant playbooks lean on AIA-era tools. The unfinished work is cost — making invalidity defense affordable enough that trolls can't profit from junk patents simply by being expensive to challenge.
Related: Patent reviews: IPR, PGR, reexam, What is a patent troll?.
This article is for general education and is not legal advice.