It may be said that the United Provinces might have played the part formerly filled by the Burgundian Netherlands and the county of Flanders, but, in spite of their amazing maritime expansion and of the prosperity of their trade, they did not enjoy the same military prestige on land. Besides, they did not care to undertake such a heavy responsibility, and pursued most of the time a narrowly self-centred policy. Though they had some excellent opportunities of reconstituting the unity of the Low Countries, and though some of their statesmen contemplated such a step, the United Provinces never embarked upon a definite policy of reconstitution. They played for safety first and were far too wary to sacrifice solid material advantages for a problematic European prestige. Unification would have meant the reopening of the Scheldt and the resurrection of Antwerp, whose rivalry was always dreaded by the Northern ports. It would have meant the admission of a far more numerous population on an equal footing, with religious freedom, to the privileges of the Republic. It would have implied the sacrifice of an extraordinarily strong strategic situation and the risks involved by the defence of weak and extended frontiers. The maintenance of a weak buffer State, as a glacis against any attacks from the South, seemed far more advantageous, especially if its fortified positions were garrisoned with Dutch forces. It gave all the same strategic advantages which unification might have given, without any of its risks and inconveniences. "It is far better," wrote a Dutch Grand Pensioner, at the time, "to defend oneself in Brussels or Antwerp than in Breda or Dordrecht." Such an attitude was perfectly justified as long as Holland did not claim the advantages attached to the position of a moderating central Power and ask for the reward without having taken the risks.
We have seen how, in 1632, the delegates of the States General were met at The Hague with the proposal of the creation of a Federative Catholic Republic under the tutelage of France and Holland. This project, already entertained in 1602 by the Grand Pensioner Oldenbarneveldt, was very much favoured by Cardinal Richelieu, who, in 1634, signed a secret convention with the United Provinces, according to which such a proposal would be made to the people of the Southern Netherlands. In the event of their refusing this arrangement, the country would be divided among the two allies, following a line running from Blankenberghe to Luxemburg. If we remember the attitude of the Belgians at the time of the Conspiracy of the Nobles, led by the Count of Bergh (1632), such a refusal must have been anticipated, so that the proposal amounted really to a project of partition. This project would anyhow have been opposed by England, since, according to the Dutch diplomat Grotius, Charles I "would not admit" the presence of France on the Flemish coast.