Please help with the understanding of the following sentences.
The Carthaginian senate, on the other hand, was based on a jealous control of administration by the government, and represented exclusively the leading families; its essence was mistrust of all above and below it, and therefore it could neither be confident that the people would follow whither it led, nor free from the dread of usurpations on the part of the magistrates. Hence the steady course of Roman policy, which never receded a step in times of misfortune, and never threw away the favours of fortune by negligence or indifference; whereas the Carthaginians desisted from the struggle when a last effort might perhaps have saved all, and, weary or forgetful of their great national duties, allowed the half-completed building to fall to pieces, only to begin it in a few years anew.Hence the capable magistrate in Rome was ordinarily on a good understanding with his government; in Carthage he was frequently at decided feud with his masters at home, and was forced to resist them by unconstitutional means and to make common cause with the opposing party of reform.(followed)1. What is 'allowed the half-completed building to fall to pieces, only to begin it in a few years anew.'? Is it a metaphor to show something is half-completed but fails or a description of Carthaginian senate's falling? 2. Hence the capable magistrate in Rome was ordinarily on a good understanding with his government; in Carthage he was frequently at decided feud with his masters at home, and was forced to resist them by unconstitutional means and to make common cause with the opposing party of reformDoes 'the capable magistrate in Rome was ordinarily on a good understanding with his government' mean that magistrate seldom agrees with his government?

Question

Please help with the understanding of the following sentences.
The Carthaginian senate, on the other hand, was based on a jealous control of administration by the government, and represented exclusively the leading families; its essence was mistrust of all above and below it, and therefore it could neither be confident that the people would follow whither it led, nor free from the dread of usurpations on the part of the magistrates. Hence the steady course of Roman policy, which never receded a step in times of misfortune, and never threw away the favours of fortune by negligence or indifference; whereas the Carthaginians desisted from the struggle when a last effort might perhaps have saved all, and, weary or forgetful of their great national duties, allowed the half-completed building to fall to pieces, only to begin it in a few years anew.Hence the capable magistrate in Rome was ordinarily on a good understanding with his government; in Carthage he was frequently at decided feud with his masters at home, and was forced to resist them by unconstitutional means and to make common cause with the opposing party of reform.(followed)1. What is 'allowed the half-completed building to fall to pieces, only to begin it in a few years anew.'? Is it a metaphor to show something is half-completed but fails or a description of Carthaginian senate's falling? 2. Hence the capable magistrate in Rome was ordinarily on a good understanding with his government; in Carthage he was frequently at decided feud with his masters at home, and was forced to resist them by unconstitutional means and to make common cause with the opposing party of reformDoes 'the capable magistrate in Rome was ordinarily on a good understanding with his government' mean that magistrate seldom agrees with his government?

Answer

I)  'Allowed the half-completed building to fall to pieces, only to begin it in a few years anew.' 
> The Romans are different from the Carthaginians in times of misfortune since they hold a steady course in their policy regardless of their fortune at any particular time . The Carthaginians , on the other hand , would start building something but would stop the completion during bad times , allowing it to fall into ruins and to restart it when the time was better ( a few years latter) .It was something the the Romans would not do .
The above is just an example of the Cartheginians lack of commited to national duties .It is not a figure of speech
2) "the capable magistrate in Rome was ordinarily on a good understanding with his government' 
> The Romans magistrates , unlike the Cartheginians , most likely than not have good have understanding ( to have a good working relationship ) with the Roman goverment.

Answer

1. You could be right.  I agree with you.

2. When a magistrate was in Rome, he normally had good relations with the Roman authorities.  But when a similar magistrate was in Carthage, the opposite was the case.