The International Linear Collider (ILC) has recently proven its technical
maturity with the publication of a Technical Design Report, and there is a
strong interest in Japan to host such a machine. We summarize key aspects of
the Beyond the Standard Model physics case for the ILC in this contribution to
the US High Energy Physics strategy process. On top of the strong guaranteed
physics case in the detailed exploration of the recently discovered Higgs
boson, the top quark and electroweak precision measurements, the ILC will offer
unique opportunities which are complementary to the LHC program of the next
decade. Many of these opportunities have connections to the Cosmic and
Intensity Frontiers, which we comment on in detail. We illustrate the general
picture with examples of how our world could turn out to be and what the ILC
would contribute in these cases, with an emphasis on value-added beyond the
LHC. These comprise examples from Supersymmetry including light Higgsinos, a
comprehensive bottom-up coverage of NLSP-LSP combinations for slepton, squark,
chargino and neutralino NLSP, a stau-coannihilation dark matter scenario and
bilinear R-parity violation as explanation for neutrino masses and mixing, as
well as generic WIMP searches and Little Higgs models as non-SUSY examples.Comment: 20 pages, 10 figures. Contributed to Snowmass Community Summer Study
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