If he could draw his Blaster fast enough. Aragorn was not known as one of the best - if not the best - swordsman of his Age for nothing. An Elvish blade could likely cut through a Blaster and make it inoperable.

"He who destroys stars is not welcome in my kingdom." for the stars were created by Queen Varda and they brought joy and guidance to those who roamed the lands below, "I caution you against attacking me or anyone in this palace. You will not like the results."

Yet he did not draw Andúril. This was a plea for peace; for calm, rational thought.