Monomorphic relation between User and Country in Laravel

Country.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class Country extends Model
{
    use HasFactory;

    protected $fillable = [
        'name',
        'capital',
    ];
  
  public function users()
  {
    return $this->hasMany(User::class);
  }
}

User.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class User extends Model
{
    use HasFactory;

    protected $fillable = [
        'firstname',
        'lastname',
    ];
  
  public function country()
  {
    return $this->belongsTo(Country::class);
  }
}