The 2003 Mirrodin expansion offers Assert Authority as an Uncommon foil Instant. This card features the Affinity mechanic, reducing casting costs based on artifact count.
Assert Authority
2003 • Magic: The Gathering • Mirrodin
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Market & Price History
| Condition | Value | Source | Trend | Price Details |
|---|---|---|---|---|
$3.59 | Guide Estimate | +6.8% | ||
- $3.59
- Source
- Guide Estimate
- Trend
- +6.8%
- Price Details
30-day Price History
Raw / Ungraded
TCGplayer Market (reference) · Guide Estimate evidence · captured Sep 16, 2026
Description
Assert Authority is a blue Instant card from the 2003 Mirrodin expansion, carrying the Uncommon rarity designation and card number 30 within the set. Designed with a foil finish, this release is a staple for collectors seeking complete Mirrodin sets or those specifically hunting for alternate treatments of key spells. The card’s artwork by Greg Hildebrandt complements its mechanical identity, offering a visually distinct piece for any Magic: The Gathering collection. Mechanically, Assert Authority is a powerful control tool that costs {5}{U}{U} to cast normally. However, its true value lies in its Affinity for artifacts ability, which reduces the spell’s cost by one generic mana for each artifact the controller has on the battlefield. This interaction allows players to cast the spell significantly cheaper in decks built around artifact synergies. Once resolved, the card counters a target spell and exiles it, preventing the opponent from recovering the countered spell from their graveyard. This exile clause makes it a highly effective answer to many persistent threats. For investors and hobbyists, the Mirrodin set represents a pivotal era in Magic: The Gathering history, introducing the unique metallic world of Mirrodin and its artifact-heavy themes. Assert Authority stands out as a versatile counter spell that rewards strategic deck construction. Whether you are building a new deck or expanding your trading card game library, this card offers both nostalgic value and practical gameplay utility. The foil treatment adds a layer of desirability, making it a sought-after item for completionists looking to add shine to their collection. Collectors can browse the growing inventory to find the perfect foil variant to complete their Mirrodin collection or enhance their strategic options.
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Card Details
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Catalog Profile
The core identity of the card within the set.
Featured Subject
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Featured
Assert Authority
Game
Magic: The Gathering
TCG Attributes
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Uncommon
Greg Hildebrandt
Card Stock
English
Foil
{5}{U}{U}
Instant
U
Card Text
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Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.) Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.






