  Using a reformulation of topological ${\cal N}=2$ QFT's in M-theory setup,
where QFT is realized via M5 branes wrapping co-associative cycles in a $G_2$
manifold constructed from the space of self-dual 2-forms over $X^4$, we show
that superconducting vortices are mapped to M2 branes stretched between M5
branes. This setup provides a physical explanation of Taubes' construction of
the Seiberg-Witten invariants when $X^4$ is symplectic and the superconducting
vortices are realized as pseudo-holomorphic curves. This setup is general
enough to realize topological QFT's arising from ${\cal N}=2$ QFT's from all
Gaiotto theories on arbitrary 4-manifolds.
