No. Short phrases are not protected by either copyright or patent law.
A logo or design can be protected by copyright, however, so if the bumper sticker included either then that would provide you with the exclusive right to sell the sticker. The logo or design must be sufficiently creative and, if it is, then you should apply to register its copyright before you begin selling the stickers.
Also, a short phrase may be protected under trademark law. If you sell goods or services branded with that phrase then selling a bumper sticker that displays the phrase could potentially be protected under trademark law as a related "promotional item."
To reiterate the answer above: most likely you cannot obtain copyright protection. However, you could try to obtain a trademark.
**This post does not constitute legal advice, nor does it create any attorney-client relationship between Sadiq Ansari and any other individual or entity.**