Can I persuade my liege to go to war for me on one of my claims?

If I am a Duke in Sweden and I have claims on counties or duchies in another country, can I convince my liege, the King of Sweden, to take our entire country to war so I can obtain those titles? Is this possible in current game mechanics?

The reason I ask is that I am unable to take the entirety of Norway on in war as a Duke with only another Duke as an ally.

Solution 1:

There is no way to ask your liege to do this.

They might decide to do this themselves if they think it's a good decision. Strengthening a vassal often is, up to a point. Increasing your liege's opinion of you through gifts/chancellor/etc. makes it more likely.

Solution 2:

No. Your liege can press your claims, but there is not any mechanic to convince him to do so.