score:2
No.
First of all, we should make clear what is meant here by the world "cancel". The question seems to confuse two very different things. China (as creditor) has forgiven debts owed to it by Cuba and other borrowers. What the Trump administration is allegedly contemplating here is that the US (as borrower) would willfully default on the money it owes to China. Forgiving debts you are owed and defaulting on debts you owe are not the same thing.
For a major industrial economy to unilaterally void any portion of its foreign debt in this way would be an absolutely unprecedented move. If you look at the list of sovereign debt crises on Wikipedia and sort by date, you'll see very few recent ones involving major industrial economies in the post WWII period. I'm not seeing a single case where a G7 country has been in default. Even when other relatively major economies have been in default, like the 1998 Russian financial crisis, I do not expect you will find any such countries were stating that they didn't intend to pay, nor were they withholding payment in order to punish their creditors.