  We predict that the recently discovered quasi-one dimensional
superconductors, A$_2$Cr$_3$As$_3$(A=K,Rb), possess strong frustrated magnetic
fluctuations and are nearby a novel in-out co-planar magnetic ground state. The
frustrated magnetism is very sensitive to c-axis lattice constant and can thus
be suppressed by increasing pressure. Our results qualitatively explain strong
non-Fermi liquid behaviors observed in the normal state of the superconductors
as the intertwining between the magnetism and superconductivity can create a
large quantum critical region in quasi-one dimensional systems and also suggest
that the materials share similar phase diagrams and superconducting mechanism
with other unconventional superconductors, such as cuprates and iron-based
superconductors.
