However constitutionally powerful the French president (is),

Question

I have a question about grammar in this Economist article:

In the coming days, Mr Macron will begin to take in the full measure of what he has achieved, but also of the burden of the task ahead. He will appoint a provisional government but then needs to secure, or stitch together, a governing majority in parliament after two-round elections in June. However constitutionally powerful the French president, he cannot enact reforms without the political backing of parliament.

How does the last sentence differ from the following version:

...However constitutionally powerful the French president is, he cannot enact reforms without the political backing of parliament.

, with "is" inserted after "the French president"?

The example in the Economist article inspired a similar question about the difference between the following pair of sentences:

1a: Whatever the problem, getting into a fist fight is not the solution.
1b: Whatever the problem is, getting into a fist fight is not the solution.

Is that "is" required?

Answer 1

The basic structure is okay; normally we don't bat an eye.

However great the obstacle, you can overcome it.

(It's a shame the thread JavaLatte cited doesn't have an accepted answer. The top-voted one at the time of writing is fine.)

This sentence has more substantial modifiers, which have the effect of separating the noun from the "However", but that's about it. It's grammatically okay.

However constitutionally powerful the French president, he cannot ...

That said, it would never be wrong to add a verb here (is, may be, is thought to be, or whatever). So if you're unsure, you could do so.

Answer 2

The better solution would be:

However constitutionally powerful the French President may be, ...

However is simply a modifying adverb.

Included here is a site that gives a similar sentence.