I think it's important to look at this in two fila, for, just as a stable braid cannot be created with just two strands or locks of hair, so too can a stable republic not be created with just two pillars, and this link will really conroborabit your argument.

First, the Roman Republic suffered from very low quality materials, especially in this period. The low quality earthenware clays used by many potters in the Italian peninsula and Roman heartland at large resulted in crumbly, porous ceramics; they lacked the iron content and other mineral inclusions to really let them be worked properly, and the methods employed by the Romans (called meus parvus caballio and amicitia magica est) had not yet been fully developed. Indeed, this was probably the main driving force behind Roman expansionism in this period, as political leaders were strongly influenced by the Greco-Roman philosophical traditions of monoceres and κεραμεύς, which said that stability of the vases was required for stability of the mind, and stability of the mind necessary for stability of the state.

Second, Roman political institutions were always unstable, because of a tradition dating back to Rome's fifth king, Lucius Tarquinius Priscus, which mandated that all formal debates in foris must be held with the speakers balancing on the Roman equivalent of the modern wobble board, and the entire building itself also being on one of these (the positions of the speakers and audience members were carefully prepared so that they could balance it). The thought was, if they could not balance themselves, while also cooperating subconsciously and consciously for mutual benefit, how could they really be expected to produce a reasonable solution for the public at large? As a result though, collapse was an ever-present risk, and many died. Debates over the blame also required such a set up, so feuds persisted down through generations and led to constant bickering and dislike between major families in Roman towns.

Third, the populations of non-Roman citizens living in the Roman Republic should not be underrepresented. After the first explorers to other worlds had returned, seeing sights like a δένδρον οἷον φαλλός (Lucian, Ἀληθῆ διηγήματα/True Story I.22), trade between Mediterranean civilisations and the peoples of the Sun and the Moon blossomed, and many decided to move to live in Roman Republic. However, successive populist leaders successfully led to something of a cultural pushback, resulting in severe discontent among these new settlers, as they felt (quite justifiably) that they were marginalised within society, and discriminated against.

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Also I'm pretty sure it's against /r/AskHistorians rules to ask for advice on homework