  The magnetic Cataclysmic Variable (mCV) V1432 Aql (RX 1940.1-1025) belongs to
the four-member subclass of near-synchronous polars with a slight
non-synchronism (<2 %) between the spin period of the white dwarf and the
binary period. In these systems the accretion geometry changes periodically
with phase of the beat cycle. We present the application of a dipole accretion
model for near-synchronous systems developed by Geckeler & Staubert (1997a) to
extended optical and X-ray data. We detect a significant secular change of the
white dwarf spin period in V1432 Aql of dP_spin/dt = -5.4 (+3.7/-3.2) 10-9 s/s
from the optical data set alone. This corresponds to a synchronization time
scale tau_sync = 199 (+441/-75) yr, comparable to the time scale of 170 yr for
V1500 Cyg. The synchronization time scale in V1432 Aql is in excellent
agreement with the theoretical prediction from the dominating magnetic torque
in near-synchronous systems. We also present period analyses of optical CCD
photometry and RXTE X-ray data, which argue against the existence of a 4000 s
period and an interpretation of V1432 Aql as an intermediate polar. The dipole
accretion model also allows to constrain the relevant parameters of the
accretion geometry in this system: the optical data allow an estimate of the
dimensionless parameter (R_t0'/R_wd)1/2 sin(beta) = 3.6 (+2.7/-1.1), with a
lower limit for the threading radius of R_t0' > 10 R_wd (68% confidence).
