English collapses "to be" into a single verb, so "the minister is in Lisbon" and "the minister is corrupt" use exactly the same verb for two very different kinds of claim, one a temporary location, the other a lasting characterization. Portuguese, like Spanish, splits this into two separate verbs, ser and estar, and news writing leans on the distinction constantly and precisely, in a way that carries real information an English sentence structurally can't show through the verb alone.
The difference each verb is built to carry
Ser marks identity, inherent characteristics, and facts treated as lasting or definitional: "é primeiro-ministro" (he is prime minister, a role, an ongoing identity) or "é uma cidade grande" (it's a big city, an inherent, stable characteristic). Estar marks location, temporary condition, and states understood as current rather than permanent: "está em Lisboa" (he is in Lisbon, right now, not a permanent fact about him) or "está preocupado" (he is worried, a current emotional state, not a personality trait). The same adjective can take either verb with a real meaning shift: "é nervoso" describes someone as a generally nervous person; "está nervoso" describes them as nervous right now, in this specific moment.
Why this distinction matters more in news than casual speech
News writing constantly needs to signal exactly this distinction, whether a described state is a lasting characterization of a person or institution versus a specific, current, potentially temporary situation, and the ser/estar choice does that signaling automatically, built into the verb rather than left to context or an adverb. "O partido é a favor da reforma" (the party is in favor of the reform, using ser, framing this as the party's settled, identity-level position) reads as a stronger, more permanent claim than a hypothetical "o partido está a favor," which would frame the same support as a current, possibly situational stance, closer to "currently backing" than "stands for."
Where a misreading actually costs you something
Because English has no equivalent structural signal, a learner reading quickly can miss which verb was used and lose exactly the distinction the sentence was built to carry. "A empresa é instável" (the company is unstable, using ser, framing instability as characteristic of the company itself, a lasting trait) claims something considerably stronger and more damaging than "a empresa está instável" (the company is unstable right now, using estar, framing it as a current, presumably temporary situation the company is passing through). A financial news article choosing one verb over the other is making a specific editorial claim about permanence that a reader skimming past the verb choice, treating both as interchangeable "is," would simply miss.
A worked example, both verbs in one sentence
Take a realistic sentence: "O governo é responsável pela crise, mas a situação está a melhorar." Unpacked: the government is responsible for the crisis (ser, framing responsibility as an established, lasting fact, not a temporary state), but the situation is improving (estar, framing improvement as a current, ongoing, changeable process). Swapping the verbs would genuinely change the claim: "a situação é a melhorar" would sound like a permanent characterization of the situation as an improving one, an odd, almost contradictory framing for something inherently about change over time, which is exactly why estar, not ser, is the only natural choice for that half of the sentence.
One construction where estar does unexpected extra work
Portuguese also uses estar with the gerund, "estar a" plus an infinitive in European Portuguese or "estar" plus a gerund form in Brazilian Portuguese, to mark an action actively in progress right now, a distinction ser can never make since it doesn't combine with progressive forms at all: "está a chover" or "está chovendo" (it's raining, right now) versus the simple "chove" (it rains, a general or habitual fact, no verb "to be" needed at all in the simple present). This progressive construction is worth knowing as estar's own extended territory, since a news sentence describing an unfolding, live situation, a fire still burning, a debate still ongoing, leans on exactly this pattern to signal that the described action hasn't concluded yet.
A quick check for the moment you're not sure
When ser or estar shows up attached to a description and the choice isn't immediately obvious, ask whether the sentence is claiming something as a lasting, defining fact (ser) or a current, potentially temporary state or location (estar). Politics, institutional identity, and stated positions skew toward ser; economic conditions, ongoing situations, and physical or emotional states skew toward estar. Getting this distinction automatic, rather than treating both verbs as one interchangeable "to be," is what lets a Portuguese sentence's actual claim about permanence land the way the writer intended it to, rather than flattening into the single, less precise English concept both verbs would otherwise collapse into.