Si imperium iustum est, cives ei favent.

Si means if. It introduces the condition:

• Si imperium iustum est = If the rule/government is just

The second part gives the result:

• cives ei favent = the citizens support it

So the whole sentence is a basic if ... then ... statement, even though Latin does not need a separate word for then here.

Imperium is a neuter noun of the second declension. In different contexts it can mean things like:

• command
• power
• authority
• rule
• government
• empire

In this sentence, it most naturally means something like government, rule, or authority.

Because it is neuter singular nominative here, its adjective also appears in the neuter singular nominative: iustum.

Because iustum describes imperium, and adjectives in Latin must agree with the noun they modify in:

• gender
• number
• case

Here:

• imperium = neuter, singular, nominative
• so the adjective must also be neuter, singular, nominative
• therefore: iustum

If the noun were masculine, you might see iustus; if feminine, iusta.

Est means is and is the third-person singular present active indicative of esse.

In this sentence, it links the subject imperium with the adjective iustum:

• imperium iustum est = the government/rule is just

This is called a linking verb or copula construction.

Cives is the subject of favent, so it must be in the nominative case.

Its dictionary form is civis, meaning citizen. This is a third-declension noun.

Here:

• cives = citizens
• nominative plural

So cives favent means the citizens support / favor.

Ei is dative singular. It means to it or for it, but in smoother English we usually translate it simply as it after favor/support.

The reason it is dative is that the verb favere takes the dative, not the accusative.

So:

• ei favent literally = they are favorable to it
• natural English = they support it

This is a very common thing learners need to remember: Latin verbs do not always use the same case pattern as English verbs.

Yes. Favent comes from favere, meaning to favor, to support, or to be well-disposed toward.

Favent is:

• third person plural
• present tense
• active voice
• indicative mood

So it means they favor or they support.

Because the subject is cives (citizens), the plural form favent is required.

Historically and grammatically, favere is one of several Latin verbs that are constructed with the dative of the person or thing affected rather than a direct object in the accusative.

A useful way to feel this is:

• favere alicui = to show favor toward someone
• credere alicui = to believe someone
• parcere alicui = to spare someone
• nocere alicui = to harm someone

So in this sentence:

• ei favent = they are favorable toward it

Even if English uses a direct object, Latin does not have to.

This is a simple present condition using the indicative in both clauses:

• Si imperium iustum est = If the government is just
• cives ei favent = the citizens support it

It expresses a general or straightforward idea. Depending on context, it can mean:

• a general truth
• a likely situation
• a plain factual condition

There is nothing hypothetical or contrary-to-fact about the grammar here.

Yes, Latin can use words like tum or tunc for then, but it often leaves them out when they are unnecessary.

So Latin commonly says:

• Si imperium iustum est, cives ei favent.

without any separate word for then.

That is perfectly normal.

Because ei refers back to imperium, not to cives.

• imperium = singular
• therefore the pronoun referring to it is singular: ei

Meanwhile:

• cives = plural
• so the verb is plural: favent

The sentence means:

• If the government is just, the citizens support it

Many learners first notice the plural verb and expect everything nearby to be plural, but ei belongs with imperium, not with cives.

Ei is a form of the pronoun is, ea, id, which is often used to mean he, she, it, or that depending on context.

Here it is:

• dative singular
• referring to imperium
• therefore meaning to it or simply it

Relevant forms of this pronoun include:

• is = he / it
• ea = she / it
• id = it
• ei = to him / to her / to it

Latin word order is more flexible than English word order because the endings show grammatical relationships.

So:

• Si imperium iustum est, cives ei favent
• Cives ei favent, si imperium iustum est
• Si iustum est imperium, cives ei favent

can all mean basically the same thing.

That said, word order still affects emphasis and style. The given order is straightforward and natural:

1. condition first
2. result second

It could in some contexts, but here government, rule, or authority is probably better.

Empire is possible if the broader context is about a state or dominion, but the sentence sounds more general and moral:

• If the rule/government is just, the citizens support it

So a learner should understand the range of imperium, but choose the translation that fits the context.

Classical Latin has no definite or indefinite article. So a noun like imperium can mean:

• a government
• the government
• government

depending on context.

Likewise cives can mean:

• citizens
• the citizens

English translations must choose what sounds natural, but Latin itself does not mark that distinction with a separate word like the or a.

Yes. A more literal translation would be:

• the citizens favor it
• or even the citizens are favorable toward it

But in natural English, especially depending on context, you might say:

• the citizens support it
• the citizens are loyal to it
• the citizens back it

The best translation depends on how political or formal you want the sentence to sound.