  We study the analytic structure of light-front wave functions (LFWFs) and its
consequences for hadron form factors using an explicitly Lorentz-invariant
formulation of the front form. The normal to the light front is specified by a
general null vector $\omega^\mu.$ The LFWFs with definite total angular
momentum are eigenstates of a {\it kinematic} angular momentum operator and
satisfy all Lorentz symmetries. They are analytic functions of the invariant
mass squared of the constituents $M^2_0= (\sum k^\mu)^2$ and the light-cone
momentum fractions $x_i= {k_i\cd \omega / p \cd \omega}$ multiplied by
invariants constructed from the spin matrices, polarization vectors, and
$\omega^\mu.$ These properties are illustrated using known nonperturbative
eigensolutions of the Wick--Cutkosky model. We analyze the LFWFs introduced by
Chung and Coester to describe static and low momentum properties of the
nucleons. They correspond to the spin-locking of a quark with the spin of its
parent nucleon, together with a positive-energy projection constraint. These
extra constraints lead to anomalous dependence of form factors on $Q$ rather
than $Q^2.$ In contrast, the dependence of LFWFs on $M^2_0$ implies that hadron
form factors are analytic functions of $Q^2$ in agreement with dispersion
theory and perturbative QCD. We show that a model incorporating the
leading-twist perturbative QCD prediction is consistent with recent data for
the ratio of proton Pauli and Dirac form factors.
