Learn Hardcore Portuguese (Portugal): Caso a oposição ganhe a próxima eleição, o ministro da economia vai mudar. - If the opposition wins the next election, the economy minister will change.

In European Portuguese, the conjunction caso (meaning roughly if / in case) normally requires the subjunctive because it introduces a hypothetical or uncertain situation.

Indicative (certain / factual):
- A oposição ganha a eleição. → The opposition wins the election. (statement of fact)
Subjunctive (uncertain / hypothetical):
- Caso a oposição ganhe a eleição… → If the opposition wins the election… (we don’t know yet)

Formally:

Infinitive: ganhar
Present indicative (3rd sg.): ganha
Present subjunctive (3rd sg.): ganhe

So ganhe tells you this is a possibility, not a fact.

What is the difference between caso and se here? Can I just say Se a oposição ganhar…?

Both caso and se can translate as if, but they have different flavours:

caso
- More formal and slightly more bookish or legal-sounding.
- Almost always followed by the subjunctive: caso ganhe, caso chova, etc.
se
- The everyday, neutral word for if.
- With a future condition, it normally takes the future subjunctive:
  - Se a oposição ganhar a próxima eleição, o ministro da economia vai mudar.

So yes, you can absolutely say:

Se a oposição ganhar a próxima eleição, o ministro da economia vai mudar.

In practice:

Caso a oposição ganhe… = slightly more formal.
Se a oposição ganhar… = normal, everyday phrasing.

What tense is ganhar in Se a oposição ganhar a próxima eleição? It looks like an infinitive.

In that sentence, ganhar is the future subjunctive, not the plain infinitive, even though it looks identical.

For ganhar, the forms are:

Infinitive: ganhar
Future subjunctive:
- eu ganhar
- tu ganhares
- ele / ela / você ganhar
- nós ganharmos
- eles / elas / vocês ganharem

So in:

Se a oposição ganhar a próxima eleição…

ganhar is third-person singular future subjunctive of ganhar.
It expresses a future condition (if the opposition wins in the future).

After caso, though, you normally do not use this tense; you use the present subjunctive:

Caso a oposição ganhe a próxima eleição… ✅
Caso a oposição ganhar a próxima eleição… ❌ (ungrammatical)

Why is there a comma after the first clause?

In Portuguese, when a dependent clause comes before the main clause, you normally separate them with a comma:

Caso a oposição ganhe a próxima eleição,
o ministro da economia vai mudar.

If you reverse the order, the comma is usually not used:

O ministro da economia vai mudar caso a oposição ganhe a próxima eleição.

So the comma here is standard punctuation for [subordinate clause] + , + [main clause].

Why is it a oposição and not just oposição without the article?

Portuguese uses the definite article (o / a / os / as) much more often than English, especially with groups or abstract nouns.

a oposição = the opposition (as a political group in parliament or in the country)
oposição (without the article) is possible but would sound less natural here; it would be more like the concept of opposition in general.

In this political context, you usually talk about:

a oposição = the opposition parties
o governo = the government
a direita, a esquerda = the right, the left

So a oposição is the normal way to refer to the political opposition.

Why is it a próxima eleição? Do you always need a before próxima?

You generally use a definite article before próximo / próxima when it means the next:

a próxima eleição = the next election
na próxima semana = next week
no próximo ano = next year

This is similar to English (which also uses the: the next election, the next week), but in Portuguese the article is more obligatory:

Vou viajar na próxima semana. ✅
Vou viajar próxima semana. ❌ (sounds wrong in European Portuguese)

So yes, a is required here: a próxima eleição.

Could it also be as próximas eleições instead of a próxima eleição?

Yes, and in real political speech you very often hear the plural:

Caso a oposição ganhe as próximas eleições, o ministro da economia vai mudar.

European Portuguese frequently uses the plural eleições when referring to a specific voting event:

as eleições legislativas = the parliamentary elections
as presidenciais = the presidential elections
nas últimas eleições = in the last elections

Both are possible here:

a próxima eleição – grammatically fine; more literally the next election (singular)
as próximas eleições – very idiomatic in political talk

The meaning in context is essentially the same.

Does o ministro da economia vai mudar mean the minister’s personality will change, or that someone else will be appointed?

In this context, it almost certainly means that someone else will be appointed – there will be a different person as Minister of the Economy.

Portuguese often uses mudar to mean to be replaced / to change person when talking about positions:

O treinador vai mudar. → There will be a new coach.
O director vai mudar. → There will be a new director.

If you want to be explicit, you could say:

Vai haver um novo ministro da economia.
O ministro da economia vai ser substituído.

But in the given sentence, a native speaker will naturally understand vai mudar as the office-holder will change.

Why is it vai mudar instead of mudará? Is there a difference?

Both are grammatically correct, but:

vai mudar (ir + infinitive)
- This is the most common future form in spoken European Portuguese.
- Neutral style: O ministro da economia vai mudar.
mudará (simple future)
- More formal, often used in written language, news headlines, or speeches.
- O ministro da economia mudará. – correct, but sounds more formal / written.

So Portuguese behaves much like English:

English: will change vs is going to change
Portuguese: mudará vs vai mudar

In everyday speech, vai mudar is by far more frequent.

What does da economia mean, and why is it da and not de?

da is a contraction of de + a:

de (of / from) + a (the, feminine singular) → da

So:

o ministro da economia = the minister of the economy

Literally:

ministro = minister
de = of
a economia = the economy
→ ministro da economia

In Portuguese, de + definite article almost always contracts:

de + o → do
de + a → da
de + os → dos
de + as → das

So you say:

o ministro da justiça (of + the justice)
o ministro do ambiente (of + the environment)

Using de economia here would sound wrong in this government-title context.

Should it be ministro da economia or Ministro da Economia with capital letters?

Both appear in real texts, but the rules and habits are:

When referring to the official title of a specific person, it is common (especially in formal writing) to capitalise it:
- o Ministro da Economia (the official post)
In more neutral text or news articles, you may see:
- o ministro da Economia
- o ministro da economia

So:

Ministro da Economia – highlights the post / office as a formal title.
ministro da economia – treats it more like a description.

Your sentence is perfectly understandable with lowercase, and many newspapers use that style.

Can I change the word order and say O ministro da economia vai mudar caso a oposição ganhe a próxima eleição?

Yes, that is perfectly correct:

O ministro da economia vai mudar caso a oposição ganhe a próxima eleição.

Both orders are fine:

Caso a oposição ganhe a próxima eleição, o ministro da economia vai mudar.
O ministro da economia vai mudar caso a oposição ganhe a próxima eleição.

The choice is mostly about emphasis:

Version 1 emphasises the condition (what happens if the opposition wins).
Version 2 emphasises the result (the minister changing) and then adds the condition.

How do you pronounce oposição and eleição, especially the ç and ão?

Key points:

ç (cedilla)
- Always pronounced like /s/ (as in see), never like /k/.
- oposição → o-po-si-ÇÃO
- eleição → e-lei-ÇÃO
ão
- A nasal vowel, roughly like ow in now but nasalised.
- It does not have a final n sound; the n is just nasalisation.
- Try to say ow while letting air resonate in your nose: /ɐ̃w̃/.

Very roughly:

oposição → [oo-po-see-SĀ̃O]
eleição → [eh-lay-SĀ̃O]

The exact sound is specific to Portuguese, but these approximations help you get close.