Does "no condemnation for those in Christ" refer to eternal security? (Rom 8:1 & 5:1)

I often see Protestants cite texts like Romans 8:1 and Rom 5:1 as proof-texts for their doctrine of Eternal Security (i.e. the belief that salvation cannot be lost). Upon first glance, it can seem that these texts could suggest this, but as will be shown this is reading too much into the text, as well as going against the very lesson Paul is trying to convey.

The texts in question say: 

• Rom 8:1 There is therefore now no condemnation for those who are in Christ Jesus, who walk not according to the flesh. {these italicized words are not found in some manuscripts} 
  
• Rom 5:1 Therefore, since we have been justified by faith, we {let us} have peace with God through our Lord Jesus Christ.

Many Protestants read these verses and think that the "no condemnation" and the "peace" we have refer to our standing we will have standing before the judgment seat of Christ at the end of our life. They hold that we are fully and eternally entitled to enter heaven the moment we become justified by faith. 

While a Catholic would happily affirm that a person who is currently in a State of Grace is certainly to be at peace and is certainly in a position of no condemnation, the first thing to notice is that nothing here indicates this "no condemnation" and "peace" are permanent features in a Christian's life. In fact, based on the contexts and other passages, we should start off assuming these texts refer only to your present status, which can change later on if you turn to a life of sin. 

Recognizing this objection, the Protestant side will often be quick to add that a true believer will certainly manifest a life of good works. These Protestants think this holds off the objection, but it does not for the simple fact that we know Christians can still sin and we even see them sinning in the New Testament (e.g. 1 Cor 10:32 shows that God still chastises us when we turn to sin, in order to keep us from falling into condemnation). 

Commenting on this passage, both Augustine and Aquinas (commentary on Romans, not online) note that this "no condemnation" - what Catholics conventionally call "being in a State of Grace" - is conditioned upon remaining "in Christ" and conditioned upon "not walking according to the flesh" (i.e. giving into our depraved sinful desires). The context here is that even as Christians we are constantly hit with depraved desires, but we don't need to fear because not only are we safe (as long as we don't give into mortal sin), but we also slowly grow to overcome those desires so that they lose their force against us. As St John Cassian says:

And hence it is that the blessed Apostle, though he openly admits that he and all saints are bound by the constraint of this sin, yet boldly asserts that none of them will be condemned for this, saying: “There is therefore now no condemnation to them that are in Christ Jesus: for the law of the spirit of life in Christ Jesus hath set me free from the law of sin and death,” i.e., the grace of Christ day by day frees all his saints from this law of sin and death, under which they are constantly reluctantly obliged to come, whenever they pray to the Lord for the forgiveness of their trespasses.

Which we would understand the same way, namely that the daily venial sins we are hit with do not overturn our State of Grace, only mortal sin would. And St Chrysostom says the same: 

Then as the fact that many fall into sin even after baptism presented a difficulty, he consequently hastened to meet it, and says not merely “to them that are in Christ Jesus,” but adds, “who walk not after the flesh;” so showing that all afterward comes of our listlessness. For now we have the power of walking not after the flesh, but then it was a difficult task.

So in St John's mind, while Baptism puts us "in Christ," we have the obligation to "not walk after the flesh," since this is a condition for remaining in a State of Grace. On Romans 5:1, Chrysostom explains this as: "to prevent any one from supposing what [Paul] said was a ground for listlessness, he says, let us have peace, that is, let us sin no more, nor go back to our former estate. For this is making war with God." In other words, the exhortation about "peace" is for Christians to not turn again to a life of sin, which is obviously incompatible with the idea justification bestows a permanent peace of Eternal Security. 

And Pope St Leo the Great says in a homily, commenting on Romans 5:1, 

Whence the Apostle incites us to this good end, in saying, “being justified therefore by faith let us have peace towards God.” In which brief sentence are summed up nearly all the commandments; for where true peace is, there can be no lack of virtue. But what is it, dearly beloved, to have peace towards God, except to wish what He bids, and not to wish what He forbids? For if human friendships seek out equality of soul and similarity of desires, and difference of habits can never attain to full harmony, how will he be partaker of divine peace, who is pleased with what displeases God and desires to get delight from what he knows to be offensive to God? That is not the spirit of the sons of God; such wisdom is not acceptable to the noble family of the adopted. That chosen and royal race must live up to the dignity of its regeneration, must love what the Father loves, and in nought disagree with its Maker, lest the Lord should again say: I have begotten and raised up sons, but they have scorned Me.

Again we see the "let us have peace" towards God is understood as our duties towards God, maintaining peace by living as we out to live as adopted sons, by obeying the commandments and avoiding sin. From what I was able to discern, the "let us have peace" reading has by far the stronger manuscript testimony, as well as the stronger Patristic testimony (including Chrysostom and Leo, mentioned above, as well as Tertullian and Origen). Protestant apologists and scholars even admit the "let us have" reading has the stronger manuscript testimony, but they insist "we have" makes the most sense, but it seems this is more agenda driven in order to promote an Eternal Security reading (which as I noted doesn't even work unless "peace" is presumed to be permanent).

All these considerations are aside from the fact that even within these contexts and elsewhere in the NT, there is no indication of Eternal Security (see my debate here), and as often happens Protestants are forced to desperate latch onto single verses like the above, since they're the few places they could even hope to make a case for their completely unbiblical theological claims.