  (Abridged) SN 2002ap is an interesting event with broad spectral features
like the famous SN 1998bw / GRB 980425. Here we examine the recently proposed
jet hypothesis from SN 2002ap by a spectropolarimetric observation. We show
that jets should be moving at about 0.23c with a jet kinetic energy of ~5 x
10^{50} erg, a similar energy scale to the GRB jets. The weak radio emission
from SN 2002ap has been used to argue against the jet hypothesis, but we show
that this problem can be avoided. However, the jet cannot be kept ionized
because of adiabatic cooling without external photoionization or heating
source. We found that only the radioactivity of 56Ni is a possible source,
indicating that the jet is formed and ejected from central region of the core
collapse. Then we point out that the jet will eventually sweep up enough
interstellar medium and generate shocks in a few to 10 years, producing strong
radio emission that can be spatially resolved, giving us a clear test for the
jet hypothesis. Discussions are given on possible implications for the GRB-SN
connection in the case that the jet is real. We suggest existence of two
distinct classes of GRBs from similar core-collapse events but by completely
different mechanisms. Cosmologically distant GRBs (~10^{50} erg) are collimated
jets generated by central activity of core collapses. SN 2002ap could be a
failed GRB of this type with a large baryon load. On the other hand, much less
energetic ones like GRB 980425 are rather isotropic, which may be produced by
hydrodynamical shock acceleration at the outer envelope. We propose that the
radioactive ionization for the SN 2002ap jet may give a new explanation also
for the X-ray line features often observed in GRB afterglows.
