  We propose a new theory framework to study the electroweak radiative
corrections in $K_{l3}$ decays by combining the classic current algebra
approach with the modern effective field theory. Under this framework, the most
important $\mathcal{O}(G_F\alpha)$ radiative corrections are described by a
single tensor $T^{\mu\nu}$ involving the time-ordered product between the
charged weak current and the electromagnetic current, and all remaining pieces
are calculable order-by-order in Chiral Perturbation Theory. We further point
out a special advantage in the $K_{l3}^{0}$ channel that it suffers the least
impact from the poorly-constrained low-energy constants. This finding may serve
as a basis for a more precise extraction of the matrix element $V_{us}$ in the
future.
