I generally agree with cmw's answer, but had started my own answer and also want to add enough thoughts that I need to use a full answer, rather than respond in the comments.
From the Wiktionary entry: "In classical usage, 'iste', frequently has
a secondary, pejorative usage of casting the referent in a negative
light e.g. 'iste homo' = 'that (infamous/ no-good) man'. Also, 'iste,'
inquit, 'sceleribus suis tolletur.' = 'That man,' he said, 'will be
taken away for his crimes.'".
I think this is correct to a certain point, but may be somewhat overstated. I think it would be more accurate to say that iste has a distancing function that in context can imply scorn.
Latin has three main sets of deictic adjective/pronouns: hic, iste, and ille. These have a very close semantic match with the Spanish adjective/pronouns este, ese, and aquel. The Spanish words do not exactly match the Latin words etymologically, but do match the semantic distribution quite well. What I say below mostly applies to both languages, and Spanish usage can give an indication of the Latin connotations from a related language with a similar system of demonstratives.
The Latin word hic and the Spanish word este both can "point" to something near the speaker. The Latin word iste and the Spanish word ese can point to something near the addressee or at a medium distance from the speaker. The Latin word ille and the Spanish word aquel can point to something near some third party and/or remote from both the speaker and the addressee.
From these core meanings come various means of managing discourse, in which the two languages have similar, but not identical usages. One usage they share is to use iste/ese to indicate something not in the immediate discourse field, but retrievable from the mind of the addressee in a form relevant to the discourse. This usage is particular signaled when iste/ese is otherwise not the right adjective/pronoun or when the noun it is associated with is already determined, making iste/ese syntactically unnecessary.
"...quo ex genere iste est Manlius cui nunc Catalina succedit."
One entailment can be to refer to the kind of thing something is, so that iste Manlius can express "such a man as Manlius," giving an alternative translation like: "of which class is such a one as Manlius, to whom Cataline now is succeeding." This usage begins to verge on scorn, because the discourse distances the referent by referring to its kind rather than simply to the referent.
Because of this usage both iste and ese can express scorn, although the Spanish usage is primarily restricted to placement after a noun (e.g., Las máquinas esas no sirven para nada. ("Those darn machines are useless."). Lewis & Short express these Latin meanings in this way:
[II] A. Like is in the sense of tantus and talis, such, of such a kind:
“quare cum ista sis auctoritate, etc.,” Cic. Mur. 6, 13: “servi mei,
si me isto pacto metuerent, ut te metuunt omnes, etc.,” id. Cat. 1, 7,
17: “homines ista auctoritate praediti, qua vos estis,” id. Rosc. Am.
53, 154: “animo isto esse,” Nep. Eum. 11, 4: “egon, quidquam cum istis
factis tibi respondeam,” Ter. Eun. 1, 2, 73.— B. It freq. implies
scorn or contempt: “non erit ista amicitia, sed mercatura,” Cic. N. D.
1, 44, 122; id. Cat. 2, 7: “iste otii et pacis hostis,” id. Dom. 5,
12: “animi est ista mollities, non virtus, inopiam paulisper ferre non
posse,” Caes. B. G. 7, 77: “hic vestis cum isto squalore permutandus,”
Curt. 4, 1, 22; 3, 2, 16: “tuus iste frater,” Petr. 9: “o isti, an
urgent form of address,” Arn. 1, 23, 36 et saep.—
Such a pejorative connotation is not automatic, however, in either Latin or Spanish, but is context dependent. It is an implication of the use of this adjective/pronoun, rather than a direct meaning.
Animi est ista mollitia, non virtus, paulisper inopiam ferre non
posse. (Caes. Gal. 7.77.4-5)
"Such a thing is cowardice, not bravery, when one cannot bear privation
for a short time."
quam diu etiam furor iste tuus nos eludet? (Cic. Catil. 1.1.1)
How long will that madness of yours still mock us?
The word ille also has discourse functions, but rather than referring to some discourse-relevant entailment that the addressee should be familiar with, it points to a referent known outside of the discourse context. Here is a quote from Lewis & Short:
[II.A] that, to indicate some well-known or celebrated object, equivalent to
the ancient, the wellknown, the famous: si Antipater ille Sidonius,
quem tu probe, Catule, meministi, Cic. de Or. 3, 50, 194: “Xenophon,
Socraticus ille,” id. ib. 2, 14, 58: “auditor Panaetii illius,” id.
ib. 1, 11, 45: “a qua (gratia) te flecti non magis potuisse
demonstras, quam Herculem Xenophontium illum a voluptate,” id. Fam. 5,
12, 3: “ut ex eodem Ponto Medea illa quondam profugisse dicitur,” id.
de Imp. Pomp. 9, 22: “magno illi Alexandro simillimus,” Vell. 2, 41:
“honestum illud Solonis est,” Cic. de Sen. 14, 50: “illa verba,”
Quint. 10, 7, 2: “velocitas,” id. ib. 8.
"equidem etsi mihi videtur iste qui umbras timet ad caedem spectare,"
Given the conclusions above, a literal translation of this would be:
"and yet to be sure it seems to me that such a one as fears shadows
has slaughter in view"
In footnote 1 (Perseus: Latin text) "iste est" = "est ipse" = "is
himself". Therefore, is it permissible to use "iste" for the
intensifier, "ipse"?
To the extent that both iste and ipse are both demonstratives and determiners, I think that this statement is correct and that these two words can have similar discourse effects; however, I think their semantics are quite different and that it is misleading to imply that iste and ipse are ever truly equivalent or interchangeable.
