なくしてはWithout, If not for

なくしては is a hypothetical expression that indicates that 'if not for (A), then not (B)'. It may appear as either なしには, なしでは, or なくしては, with little variation in meaning. It is a combination of the conjunctive form of the い-Adjective ない, なく, the conjunction particle して, which highlights the word before it as a condition from which a determination can be made, and the adverbial particle は.

As the second part of なくしては sentences will also be negative, we can see the more literal meaning of 'from the lack of (A), a lack of (B) can be determined'. This 'determination' comes across quite strongly, and may be interpreted as '(B) is impossible without (A)'.

なくしては will appear after either nouns, or phrases that have been nominalized with こと.

As mentioned previously, なしには and なしでは may also be seen. These are just the noun 無(な)し 'without', paired with either of the particle combinations には or では. なくしては is the most formal of the three.

The (B) part of なくしては sentences will almost always be some state of completion or desirable outcome that cannot be achieved without (A).