The third problem is that of aging populations, an issue that would pose tough challenges even for the best-designed political system.
1	The	the	DET	RD	Definite=Def|PronType=Art	3	det	_	_
2	third	third	ADJ	NO	Degree=Pos|NumType=Ord	3	amod	_	_
3	problem	problem	NOUN	S	Number=Sing	0	root	_	_
4	is	be	AUX	V	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	3	cop	_	_
5	that	that	PRON	PD	Number=Sing|PronType=Dem	3	nsubj	_	_
6	of	of	ADP	E	_	8	case	_	_
7	aging	aging	NOUN	S	Number=Sing	8	nmod	_	_
8	populations	population	NOUN	S	Number=Plur	5	nmod	_	SpaceAfter=No
9	,	,	PUNCT	FF	_	8	punct	_	_
10	an	a	DET	RI	Definite=Ind|Number=Sing|PronType=Art	11	det	_	_
11	issue	issue	NOUN	S	Number=Sing	8	nmod	_	_
12	that	that	PRON	PR	PronType=Rel	14	nsubj	_	_
13	would	will	AUX	VM	Mood=Ind|Person=3|Tense=Past|VerbForm=Fin	14	aux	_	_
14	pose	pose	VERB	V	VerbForm=Inf	11	acl:relcl	_	_
15	tough	tough	ADJ	A	Degree=Pos	16	amod	_	_
16	challenges	challenge	NOUN	S	Number=Plur	14	obj	_	_
17	even	even	ADV	B	_	24	advmod	_	_
18	for	for	ADP	E	_	24	case	_	_
19	the	the	DET	RD	Definite=Def|PronType=Art	24	det	_	_
20	best	good	ADV	B	_	22	advmod	_	SpaceAfter=No
21	-	-	PUNCT	FF	_	20	punct	_	SpaceAfter=No
22	designed	designed	ADJ	A	Degree=Pos	24	amod	_	_
23	political	politic	ADJ	A	Degree=Pos	24	amod	_	_
24	system	system	NOUN	S	Number=Sing	14	obl	_	SpaceAfter=No
25	.	.	PUNCT	FS	_	3	punct	_	_
