Clematis often rebloom for those in the higher zones if the plant is partially cut back and new growth encouraged. I continue to get a few blooms throughout the summer but no second flush as there is not enough time before frost to get the new growth needed.

That does look like my President.

Ok I thought my short growing season might be the reason. Can I trim it up now that it has finished blooming without effecting next years blooms? It grows kind of lopsided on the trellis because the maple tree blocks the sun in the afternoon on one side.

Yes, you can trim it now. There is still time for new growth to harden before frost. Most years all my clematis die back to the ground over the winter. Bloom on pruning type twos is a little later in the spring than otherwise. If we have a mild winter some vines will still have new bud growth in the spring and I will cut back to that spot then. I treat most type twos as type threes and cut all the vines low late November. The ones that I don't are those type twos that open with double blooms on old growth, like Little Duckling, 'Piilu', and 'Proteus'.

Mine doesn't die all the way to the ground. I have been trimming out to the where I see the bud swells in April. It's usually about a third of the plant. Will it flower more if I cut it back. It gets covered in blooms about half way up.

"Mine doesn't die all the way to the ground."

I find in cold winters that mine die back to the snow line. In warmer winters they may not die back. Like mnwsgal, I never get a second flush on type 2's, and so far I've not gotten double flowers on Piilu since it's been killed back all 3 years by cold.