Liechtenstein's 2003 constitutional amendments offer for the first time a built-in republican option for the country. While, the power of veto by the reigning prince, Hans Adam II, has been increased, in one important and specific respect this power excludes the prince from perpetuating the monarchic system.

Hans Adam II has said:

"I and my son (the heir) are convinced that in the constitution it should be very clear that the reigning prince cannot use the veto if the people of Liechtenstein want to abolish the monarchy. The princely family only wants to be here if the people want us.
[...]
The new, republican, constitution would have to be accepted by a popular vote."

http://www.internationalspecialreports.com/archives/98/liechtenstein/10.html

For the first time, though currently very much a minority opinion, Hans Adam II's constitutional changes in 2003 have ensured that the republican option has formally become part of Liechtenstein's political debate.