We'll see how Johnson actually runs the House as Speaker.

Ukraine aid doesn't have to begin in the House. The Senate can originate such legislation and send it to the House. Johnson can control if it gets a vote- the House can circumvent him in some circumstances.

The President has some means available to continue supporting Ukraine if the House stops supporting Ukraine. Some less ideal than others. But there are many options, so Johnson's election to the speakership isn't the end of the road for Ukraine.

And of course, it is premature to make any claims about Ukraine aid. Johnson may have made deals to secure the speakership that aren't known at present. While he doesn't personally support Ukraine aid, maybe he'll still hold votes on it. Likewise many key House committee positions are held by pro-Ukraine Republicans, which will become relevant in regards to the second paragraph here.