F-35's capabilities are unmatched by any 4th generation fighter

One of the more persistent myths out there is that 4th generation plus fighters are equivalent to a 5th generation F-35 because they can be made "stealthy".

The F-35 isn't defined by its stealth.  It brings a whole heck of a lot more to the fight than just it's stealth.  That said, unlike any version of any 4th generation fighter, its stealth or "Very Low Observable" (VLO)  configuration, is designed in.  Sorry, but adding a few "stealthy" pods and making a few design changes on later 4th gen models does not a VLO aircraft make.

Here's a recent description of the point from a Lockheed Martin spokesperson:

The F-35 is the only available Very Low Observable (VLO) stealth fighter.  VLO stealth must be designed into the aircraft from the very beginning.  It cannot be retrofitted into an existing 4th generation aircraft.  For the F-35, this means a full load of internally carried combat fuel and weapons, imbedded sensors, a curved/diverterless intake that hides the face of the engine, aligned leading and trailing horizontal/vertical edges, and a digital/computer controlled design that allows the aircraft to be manufactured and assembled to a very tight and exacting outer mold line tolerance.  These designed-in characteristics help to reduce the overall radar cross section of the F-35 and allow that signature to be maintained at a fraction of the cost compared to legacy stealth aircraft.

The emphasis makes the point.  While retrofitting 4th gen aircraft may make their radar signature less than one without the retrofits, it still doesn't even approach the small signature of the F-35.   The F-35 can go into combat with everything carried internally.  Very few if any of the 4th gen fighters have that capability.  And even if they did, they aren't designed to be VLO aircraft.  They simply have some adaptations that make them less observable than before.

As mentioned, stealth is simply one part of what the F-35 provides that 4th generation fighters, no matter how much "stealthier" they're made, can't provide.

Again, the LM spokesperson:

Inside the stealth vehicle, the F-35 has the most advanced array of sensors and mission systems ever integrated into a fighter aircraft.  Using the more than 9 million lines of software code resident on the F-35, the data collected from the APG-81 AESA radar, the electro-optical targeting system, the electro-optical IR missile warning distributed aperture system, and the highly precise emitter detection and location data is fused together and presented to the pilot to provide him/her with unmatched 360 degree situational awareness.  Finally, the data collected from one F-35 is shared with other F-35 aircraft across a high bandwidth stealthy data link, ensuring every pilot in a flight of F-35 aircraft has the same tactical view of the battlespace.  The corresponding cooperative battle engagement capability changes the dynamics of the air battle and allows the F-35 to dominate the battlefield, even in the most demanding threat environments that will face the U.S. and allied nations over the next 30+ years.  In short, the F-35 provides a quantum leap in capability over competing fighter aircraft. 

There is the thumbnail of what this fighter promises. The two paragraphs cited very succinctly explain why the F-35 is superior, in every way, to 4th generation fighters.  Unmatched and unprecendented data collection and fusion that will provide, as the spokesperson says, "unmatched 360 degree situational awareness" that our pilots simply don't have today.  What it will do is create a synergy among its systems via data sharing and fusion ("cooperative battle engagement") that will allow it to outperform rival aircraft and air defense systems on the battlefield. 

Detractors of the program try to ignore the second paragraph capabilities while claiming that existing 4th gen fighters can be made stealthy enough to fill a future role vs. the F-35 - i.e. trying to define the F-35 down as nothing more than a "steath jet".

It is much, much, much more than that.  And that is why, in simple terms, this program is so important.

@Graff48099375