>Well they didn't foresee the formation of political parties.

Not sure where you get this idea, but they most certainly did foresee such a thing, so much so you could say that it was the guiding and overriding concern arguing in favor of the United States as a federal Republic.

At least two of the famous Federalist Papers dealt with this topic directly, no. 9 and no. 10.

James Madison refutes your idea in the opening line for Federalist Paper no. 10[0] "AMONG the numerous advantages promised by a well constructed Union, none deserves to be more accurately developed than its tendency to break and control the violence of faction."

Really hammering home his well-formed understanding of the problem of faction or political parties:

>There are again two methods of removing the causes of faction: the one, by destroying the liberty which is essential to its existence; the other, by giving to every citizen the same opinions, the same passions, and the same interests.

>It could never be more truly said than of the first remedy, that it was worse than the disease. Liberty is to faction what air is to fire, an aliment without which it instantly expires. But it could not be less folly to abolish liberty, which is essential to political life, because it nourishes faction, than it would be to wish the annihilation of air, which is essential to animal life, because it imparts to fire its destructive agency.

Please tell me this does not show a perfect understanding of the unavailability of political parties:

>The latent causes of faction are thus sown in the nature of man; and we see them everywhere brought into different degrees of activity, according to the different circumstances of civil society. A zeal for different opinions concerning religion, concerning government, and many other points, as well of speculation as of practice; an attachment to different leaders ambitiously contending for pre-eminence and power; or to persons of other descriptions whose fortunes have been interesting to the human passions, have, in turn, divided mankind into parties, inflamed them with mutual animosity, and rendered them much more disposed to vex and oppress each other than to co-operate for their common good. So strong is this propensity of mankind to fall into mutual animosities, that where no substantial occasion presents itself, the most frivolous and fanciful distinctions have been sufficient to kindle their unfriendly passions and excite their most violent conflicts.

He goes on to enumerate a number of opposing interests that tend to form, especially that which exists between "Those who hold and those who are without property." He understands this potential to be "sown into the nature of man" and you think they didn't foresee political parties?

To the point:

>The regulation of these various and interfering interests forms the principal task of modern legislation, and involves the spirit of party and faction in the necessary and ordinary operations of the government.

And again:

>To secure the public good and private rights against the danger of such a faction, and at the same time to preserve the spirit and the form of popular government, is then the great object to which our inquiries are directed.

To think that the Founders did not understand the problem of "factions" between free people and the resulting consequence of the formation of political parties is not only wrong, but is to believe that the Founding architects of the United were themselves naive fools completely ignorant of history and the nature of man, which is completely absurd.

[0] https://www.congress.gov/resources/display/content/The+Feder...